✨(freebusy) add availability management (#35)

Adds organization-level default calendar sharing controls, "Find a Time" scheduling UI with a Free/Busy timeline showing attendee availability and conflicts, Working hours editor in Settings to manage and save availability, Autocomplete attendee search with debounced, partial name/email matching and timezone display. Fixes #26. Fixes #25. Fixes #24.
2026-03-10 01:30:42 +01:00
parent 9c18f96090
commit 7cb8d5e7b6
49 changed files with 3714 additions and 246 deletions
--- a/README.md
+++ b/README.md
@@ -82,12 +82,20 @@ Your Docker services should now be up and running! 🎉

 You can access the project by going to <http://localhost:8930>.

-You will be prompted to log in. The default credentials are:
+You will be prompted to log in. The following test users are
+pre-configured in Keycloak (password = username prefix):

-```
-username: calendars
-password: calendars
-```
+| Email | Password | Org domain |
+|---|---|---|
+| `user1@example.local` | `user1` | `example.local` |
+| `user2@example.local` | `user2` | `example.local` |
+| `user3@example.local` | `user3` | `example.local` |
+| `user1.2@example2.local` | `user1.2` | `example2.local` |
+| `user2.2@example2.local` | `user2.2` | `example2.local` |
+
+Users sharing the same domain are placed in the same organization
+automatically on first login. Use users from different domains
+(`example.local` vs `example2.local`) to test cross-org isolation.

 Note that if you need to run them afterward, you can use the eponym Make rule:

--- a/compose.yaml
+++ b/compose.yaml
@@ -11,6 +11,8 @@ services:
      interval: 1s
      timeout: 2s
      retries: 300
+    volumes:
+      - ./docker/postgresql/init-databases.sh:/docker-entrypoint-initdb.d/init-databases.sh:ro
    env_file:
      - env.d/development/postgresql.defaults
      - env.d/development/postgresql.local
--- a/docker/auth/realm.json
+++ b/docker/auth/realm.json
@@ -51,15 +51,71 @@
    "failureFactor": 30,
    "users": [
      {
-        "username": "calendars",
-        "email": "calendars@calendars.world",
-        "firstName": "John",
-        "lastName": "Doe",
+        "username": "user1",
+        "email": "user1@example.local",
+        "firstName": "User",
+        "lastName": "One",
        "enabled": true,
        "credentials": [
          {
            "type": "password",
-            "value": "calendars"
+            "value": "user1"
+          }
+        ],
+        "realmRoles": ["user"]
+      },
+      {
+        "username": "user2",
+        "email": "user2@example.local",
+        "firstName": "User",
+        "lastName": "Two",
+        "enabled": true,
+        "credentials": [
+          {
+            "type": "password",
+            "value": "user2"
+          }
+        ],
+        "realmRoles": ["user"]
+      },
+      {
+        "username": "user3",
+        "email": "user3@example.local",
+        "firstName": "User",
+        "lastName": "Three",
+        "enabled": true,
+        "credentials": [
+          {
+            "type": "password",
+            "value": "user3"
+          }
+        ],
+        "realmRoles": ["user"]
+      },
+      {
+        "username": "user1.2",
+        "email": "user1.2@example2.local",
+        "firstName": "User",
+        "lastName": "One-Bis",
+        "enabled": true,
+        "credentials": [
+          {
+            "type": "password",
+            "value": "user1.2"
+          }
+        ],
+        "realmRoles": ["user"]
+      },
+      {
+        "username": "user2.2",
+        "email": "user2.2@example2.local",
+        "firstName": "User",
+        "lastName": "Two-Bis",
+        "enabled": true,
+        "credentials": [
+          {
+            "type": "password",
+            "value": "user2.2"
          }
        ],
        "realmRoles": ["user"]
--- a/src/backend/calendars/settings.py
+++ b/src/backend/calendars/settings.py
@@ -83,6 +83,15 @@ class Base(Configuration):
    CALDAV_INTERNAL_API_KEY = SecretFileValue(
        None, environ_name="CALDAV_INTERNAL_API_KEY", environ_prefix=None
    )
+
+    # Default calendar sharing level for new organizations.
+    # Controls what colleagues in the same org can see by default.
+    # Values: "none", "freebusy", "read", "write"
+    ORG_DEFAULT_SHARING_LEVEL = values.Value(
+        "freebusy",
+        environ_name="ORG_DEFAULT_SHARING_LEVEL",
+        environ_prefix=None,
+    )
    # Salt for django-fernet-encrypted-fields (Channel tokens, etc.)
    # Used with SECRET_KEY to derive Fernet encryption keys via PBKDF2
    SALT_KEY = values.Value(
@@ -931,8 +940,8 @@ class Development(Base):
    EMAIL_PORT = 1025
    EMAIL_USE_TLS = False
    EMAIL_USE_SSL = False
-    DEFAULT_FROM_EMAIL = "calendars@calendars.world"
-    CALENDAR_INVITATION_FROM_EMAIL = "calendars@calendars.world"
+    DEFAULT_FROM_EMAIL = "noreply@example.local"
+    CALENDAR_INVITATION_FROM_EMAIL = "noreply@example.local"
    APP_NAME = "Calendars (dev)"
    APP_URL = "http://localhost:8931"

--- a/src/backend/core/api/serializers.py
+++ b/src/backend/core/api/serializers.py
@@ -4,6 +4,7 @@ from django.conf import settings
 from django.utils.text import slugify

 from rest_framework import serializers
+from timezone_field.rest_framework import TimeZoneSerializerField

 from core import models
 from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
@@ -13,10 +14,16 @@ from core.models import uuid_to_urlsafe
 class OrganizationSerializer(serializers.ModelSerializer):
    """Serialize organizations."""

+    sharing_level = serializers.SerializerMethodField(read_only=True)
+
    class Meta:
        model = models.Organization
-        fields = ["id", "name"]
-        read_only_fields = ["id", "name"]
+        fields = ["id", "name", "sharing_level"]
+        read_only_fields = ["id", "name", "sharing_level"]
+
+    def get_sharing_level(self, org) -> str:
+        """Return the effective sharing level (org override or server default)."""
+        return org.effective_sharing_level


 class UserLiteSerializer(serializers.ModelSerializer):
@@ -32,6 +39,7 @@ class UserSerializer(serializers.ModelSerializer):
    """Serialize users."""

    email = serializers.SerializerMethodField(read_only=True)
+    timezone = TimeZoneSerializerField(use_pytz=False)

    class Meta:
        model = models.User
@@ -40,6 +48,7 @@ class UserSerializer(serializers.ModelSerializer):
            "email",
            "full_name",
            "language",
+            "timezone",
        ]
        read_only_fields = ["id", "email", "full_name"]

--- a/src/backend/core/api/viewsets.py
+++ b/src/backend/core/api/viewsets.py
@@ -5,6 +5,7 @@ import logging

 from django.conf import settings
 from django.core.cache import cache
+from django.db.models import Q
 from django.utils.text import slugify

 from rest_framework import mixins, pagination, response, status, views, viewsets
@@ -98,9 +99,9 @@ class UserViewSet(

    def get_queryset(self):
        """
-        Limit listed users by querying the email field.
+        Limit listed users by querying email or full_name.
        Scoped to the requesting user's organization.
-        If query contains "@", search exactly. Otherwise return empty.
+        Minimum 3 characters required.
        """
        queryset = self.queryset

@@ -112,15 +113,13 @@ class UserViewSet(
            return queryset.none()
        queryset = queryset.filter(organization_id=self.request.user.organization_id)

-        if not (query := self.request.query_params.get("q", "")) or len(query) < 5:
+        if not (query := self.request.query_params.get("q", "")) or len(query) < 3:
            return queryset.none()

-        # For emails, match exactly
-        if "@" in query:
-            return queryset.filter(email__iexact=query).order_by("email")
-
-        # For non-email queries, return empty (no fuzzy search)
-        return queryset.none()
+        # Search by email (partial, case-insensitive) or full name
+        return queryset.filter(
+            Q(email__icontains=query) | Q(full_name__icontains=query)
+        ).order_by("full_name", "email")[:50]

    @action(
        detail=False,
@@ -210,6 +209,57 @@ class ConfigView(views.APIView):
        return theme_customization


+class OrganizationSettingsViewSet(viewsets.ViewSet):
+    """ViewSet for organization settings (sharing level, etc.).
+
+    Only org admins can update settings; all org members can read them.
+    """
+
+    permission_classes = [IsAuthenticated]
+
+    def retrieve(self, request, pk=None):  # pylint: disable=unused-argument
+        """GET /api/v1.0/organization-settings/current/"""
+        org = request.user.organization
+        if not org:
+            return response.Response(
+                {"detail": "User has no organization."},
+                status=status.HTTP_404_NOT_FOUND,
+            )
+        return response.Response(serializers.OrganizationSerializer(org).data)
+
+    def partial_update(self, request, pk=None):  # pylint: disable=unused-argument
+        """PATCH /api/v1.0/organization-settings/current/"""
+        if not request.user.organization:
+            return response.Response(
+                {"detail": "User has no organization."},
+                status=status.HTTP_404_NOT_FOUND,
+            )
+
+        # Check admin permission
+        perm = permissions.IsOrgAdmin()
+        if not perm.has_permission(request, self):
+            return response.Response(
+                {"detail": "Only org admins can update settings."},
+                status=status.HTTP_403_FORBIDDEN,
+            )
+
+        org = request.user.organization
+        sharing_level = request.data.get("default_sharing_level")
+        if sharing_level is not None:
+            valid = {c[0] for c in models.SharingLevel.choices}
+            if sharing_level not in valid:
+                return response.Response(
+                    {
+                        "detail": f"Invalid sharing level. Must be one of: {', '.join(valid)}"
+                    },
+                    status=status.HTTP_400_BAD_REQUEST,
+                )
+            org.default_sharing_level = sharing_level
+            org.save(update_fields=["default_sharing_level", "updated_at"])
+
+        return response.Response(serializers.OrganizationSerializer(org).data)
+
+
 class CalendarViewSet(viewsets.GenericViewSet):
    """ViewSet for calendar operations.

--- a/src/backend/core/migrations/0002_organization_default_sharing_level.py
+++ b/src/backend/core/migrations/0002_organization_default_sharing_level.py
@@ -0,0 +1,18 @@
+# Generated by Django 5.2.9 on 2026-03-09 08:25
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='organization',
+            name='default_sharing_level',
+            field=models.CharField(blank=True, choices=[('none', 'No sharing'), ('freebusy', 'Free/Busy only'), ('read', 'Read access'), ('write', 'Read/Write access')], help_text='Default calendar sharing level for org members. Null means use the server-wide default (ORG_DEFAULT_SHARING_LEVEL).', max_length=10, null=True),
+        ),
+    ]
--- a/src/backend/core/models.py
+++ b/src/backend/core/models.py
@@ -66,6 +66,15 @@ class BaseModel(models.Model):
        super().save(*args, **kwargs)


+class SharingLevel(models.TextChoices):
+    """Calendar sharing visibility levels within an organization."""
+
+    NONE = "none", "No sharing"
+    FREEBUSY = "freebusy", "Free/Busy only"
+    READ = "read", "Read access"
+    WRITE = "write", "Read/Write access"
+
+
 class Organization(BaseModel):
    """Organization model, populated from OIDC claims and entitlements.

@@ -81,6 +90,16 @@ class Organization(BaseModel):
        db_index=True,
        help_text="Organization identifier from OIDC claim or email domain.",
    )
+    default_sharing_level = models.CharField(
+        max_length=10,
+        choices=SharingLevel.choices,
+        null=True,
+        blank=True,
+        help_text=(
+            "Default calendar sharing level for org members. "
+            "Null means use the server-wide default (ORG_DEFAULT_SHARING_LEVEL)."
+        ),
+    )

    class Meta:
        db_table = "calendars_organization"
@@ -90,6 +109,13 @@ class Organization(BaseModel):
    def __str__(self):
        return self.name or self.external_id

+    @property
+    def effective_sharing_level(self):
+        """Return the effective sharing level, falling back to server default."""
+        if self.default_sharing_level:
+            return self.default_sharing_level
+        return settings.ORG_DEFAULT_SHARING_LEVEL
+
    def delete(self, *args, **kwargs):
        """Delete org after cleaning up members' CalDAV data.

--- a/src/backend/core/services/caldav_service.py
+++ b/src/backend/core/services/caldav_service.py
@@ -58,11 +58,15 @@ class CalDAVHTTPClient:
        """
        if not user.email:
            raise ValueError("User has no email address")
-        return {
+        headers = {
            "X-Api-Key": cls.get_api_key(),
            "X-Forwarded-User": user.email,
            "X-CalDAV-Organization": str(user.organization_id),
        }
+        org = getattr(user, "organization", None)
+        if org and hasattr(org, "effective_sharing_level"):
+            headers["X-CalDAV-Sharing-Level"] = org.effective_sharing_level
+        return headers

    def build_url(self, path: str, query: str = "") -> str:
        """Build a full CalDAV URL from a resource path.
--- a/src/backend/core/tests/test_api_users.py
+++ b/src/backend/core/tests/test_api_users.py
@@ -73,61 +73,38 @@ def test_api_users_list_query_inactive():


 def test_api_users_list_query_short_queries():
-    """
-    Queries shorter than 5 characters should return an empty result set.
-    """
-
+    """Queries shorter than 3 characters should return an empty result set."""
    user = factories.UserFactory()
+    org = user.organization
    client = APIClient()
    client.force_login(user)

-    factories.UserFactory(email="john.doe@example.com")
-    factories.UserFactory(email="john.lennon@example.com")
+    factories.UserFactory(email="john.doe@example.com", organization=org)

    response = client.get("/api/v1.0/users/?q=jo")
    assert response.status_code == 200
    assert response.json()["results"] == []

-    response = client.get("/api/v1.0/users/?q=john")
-    assert response.status_code == 200
-    assert response.json()["results"] == []
-
-    # Non-email queries (without @) return empty
-    response = client.get("/api/v1.0/users/?q=john.")
+    response = client.get("/api/v1.0/users/?q=j")
    assert response.status_code == 200
    assert response.json()["results"] == []


-def test_api_users_list_limit(settings):
-    """
-    Authenticated users should be able to list users and the number of results
-    should be limited to 10.
-    """
+def test_api_users_list_limit(settings):  # pylint: disable=unused-argument
+    """Results should be bounded even with many matching users."""
    user = factories.UserFactory()
    org = user.organization

    client = APIClient()
    client.force_login(user)

-    # Use a base name with a length equal 5 to test that the limit is applied
-    base_name = "alice"
-    for i in range(15):
-        factories.UserFactory(email=f"{base_name}.{i}@example.com", organization=org)
+    for i in range(55):
+        factories.UserFactory(email=f"alice.{i}@example.com", organization=org)

-    # Non-email queries (without @) return empty
-    response = client.get(
-        "/api/v1.0/users/?q=alice",
-    )
+    # Partial match returns results (capped at 50)
+    response = client.get("/api/v1.0/users/?q=alice")
    assert response.status_code == 200
-    assert response.json()["results"] == []
-
-    # Email queries require exact match
-    settings.API_USERS_LIST_LIMIT = 100
-    response = client.get(
-        "/api/v1.0/users/?q=alice.0@example.com",
-    )
-    assert response.status_code == 200
-    assert len(response.json()["results"]) == 1
+    assert len(response.json()["results"]) == 50


 def test_api_users_list_throttling_authenticated(settings):
@@ -154,8 +131,7 @@ def test_api_users_list_throttling_authenticated(settings):

 def test_api_users_list_query_email(settings):
    """
-    Authenticated users should be able to list users and filter by email.
-    Only exact email matches are returned (case-insensitive).
+    Authenticated users should be able to search users by partial email.
    """

    settings.REST_FRAMEWORK["DEFAULT_THROTTLE_RATES"]["user_list_burst"] = "9999/minute"
@@ -167,42 +143,35 @@ def test_api_users_list_query_email(settings):
    client.force_login(user)

    dave = factories.UserFactory(email="david.bowman@work.com", organization=org)
-    factories.UserFactory(email="nicole.bowman@work.com", organization=org)
+    nicole = factories.UserFactory(email="nicole.bowman@work.com", organization=org)

    # Exact match works
-    response = client.get(
-        "/api/v1.0/users/?q=david.bowman@work.com",
-    )
+    response = client.get("/api/v1.0/users/?q=david.bowman@work.com")
    assert response.status_code == 200
-    user_ids = [user["id"] for user in response.json()["results"]]
-    assert user_ids == [str(dave.id)]
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(dave.id) in user_ids
+
+    # Partial email match works
+    response = client.get("/api/v1.0/users/?q=bowman@work")
+    assert response.status_code == 200
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(dave.id) in user_ids
+    assert str(nicole.id) in user_ids

    # Case-insensitive match works
-    response = client.get(
-        "/api/v1.0/users/?q=David.Bowman@Work.COM",
-    )
+    response = client.get("/api/v1.0/users/?q=David.Bowman@Work.COM")
    assert response.status_code == 200
-    user_ids = [user["id"] for user in response.json()["results"]]
-    assert user_ids == [str(dave.id)]
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(dave.id) in user_ids

-    # Typos don't match (exact match only)
-    response = client.get(
-        "/api/v1.0/users/?q=davig.bovman@worm.com",
-    )
+    # Typos don't match
+    response = client.get("/api/v1.0/users/?q=davig.bovman@worm.com")
    assert response.status_code == 200
-    user_ids = [user["id"] for user in response.json()["results"]]
-    assert user_ids == []
-
-    response = client.get(
-        "/api/v1.0/users/?q=davig.bovman@worm.cop",
-    )
-    assert response.status_code == 200
-    user_ids = [user["id"] for user in response.json()["results"]]
-    assert user_ids == []
+    assert response.json()["results"] == []


-def test_api_users_list_query_email_matching():
-    """Email queries return exact matches only (case-insensitive)."""
+def test_api_users_list_query_email_partial_matching():
+    """Partial email queries return matching users."""
    user = factories.UserFactory()
    org = user.organization

@@ -212,29 +181,111 @@ def test_api_users_list_query_email_matching():
    user1 = factories.UserFactory(
        email="alice.johnson@example.gouv.fr", organization=org
    )
-    factories.UserFactory(email="alice.johnnson@example.gouv.fr", organization=org)
+    user2 = factories.UserFactory(
+        email="alice.johnnson@example.gouv.fr", organization=org
+    )
    factories.UserFactory(email="alice.kohlson@example.gouv.fr", organization=org)
    user4 = factories.UserFactory(
        email="alicia.johnnson@example.gouv.fr", organization=org
    )
-    factories.UserFactory(email="alicia.johnnson@example.gov.uk", organization=org)
+    # Different org user should not appear
+    other_org_user = factories.UserFactory(email="alice.johnnson@example.gov.uk")
    factories.UserFactory(email="alice.thomson@example.gouv.fr", organization=org)

-    # Exact match returns only that user
-    response = client.get(
-        "/api/v1.0/users/?q=alice.johnson@example.gouv.fr",
-    )
+    # Partial match on "alice.john" returns alice.johnson and alice.johnnson
+    response = client.get("/api/v1.0/users/?q=alice.john")
    assert response.status_code == 200
-    user_ids = [user["id"] for user in response.json()["results"]]
-    assert user_ids == [str(user1.id)]
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(user1.id) in user_ids
+    assert str(user2.id) in user_ids
+    assert str(other_org_user.id) not in user_ids

-    # Different email returns different user
-    response = client.get("/api/v1.0/users/?q=alicia.johnnson@example.gouv.fr")
+    # Partial match on "alicia" returns alicia.johnnson (same org only)
+    response = client.get("/api/v1.0/users/?q=alicia")
    assert response.status_code == 200
-    user_ids = [user["id"] for user in response.json()["results"]]
+    user_ids = [u["id"] for u in response.json()["results"]]
    assert user_ids == [str(user4.id)]


+def test_api_users_list_query_by_name():
+    """Users should be searchable by full name (partial, case-insensitive)."""
+    user = factories.UserFactory()
+    org = user.organization
+
+    client = APIClient()
+    client.force_login(user)
+
+    alice = factories.UserFactory(
+        email="alice@example.com", full_name="Alice Johnson", organization=org
+    )
+    bob = factories.UserFactory(
+        email="bob@example.com", full_name="Bob Smith", organization=org
+    )
+    factories.UserFactory(
+        email="charlie@example.com", full_name="Charlie Johnson", organization=org
+    )
+
+    # Search by first name
+    response = client.get("/api/v1.0/users/?q=Alice")
+    assert response.status_code == 200
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(alice.id) in user_ids
+    assert str(bob.id) not in user_ids
+
+    # Search by last name matches multiple users
+    response = client.get("/api/v1.0/users/?q=Johnson")
+    assert response.status_code == 200
+    assert len(response.json()["results"]) == 2
+
+    # Case-insensitive
+    response = client.get("/api/v1.0/users/?q=bob")
+    assert response.status_code == 200
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(bob.id) in user_ids
+
+
+def test_api_users_list_cross_org_isolation():
+    """Users from different organizations should not see each other."""
+    org1 = factories.OrganizationFactory(name="Org One")
+    org2 = factories.OrganizationFactory(name="Org Two")
+
+    user1 = factories.UserFactory(
+        email="user1@org1.com", full_name="Shared Name", organization=org1
+    )
+    factories.UserFactory(
+        email="user2@org2.com", full_name="Shared Name", organization=org2
+    )
+
+    client = APIClient()
+    client.force_login(user1)
+
+    # Search by shared name - should only return same-org user
+    response = client.get("/api/v1.0/users/?q=Shared")
+    assert response.status_code == 200
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(user1.id) in user_ids
+    assert len(user_ids) == 1
+
+    # Search by cross-org email - should return nothing
+    response = client.get("/api/v1.0/users/?q=user2@org2.com")
+    assert response.status_code == 200
+    assert response.json()["results"] == []
+
+
+def test_api_users_list_includes_self():
+    """Search should include the requesting user if they match."""
+    user = factories.UserFactory(email="alice@example.com", full_name="Alice Test")
+
+    client = APIClient()
+    client.force_login(user)
+
+    # User should find themselves
+    response = client.get("/api/v1.0/users/?q=alice")
+    assert response.status_code == 200
+    user_ids = [u["id"] for u in response.json()["results"]]
+    assert str(user.id) in user_ids
+
+
 def test_api_users_retrieve_me_anonymous():
    """Anonymous users should not be allowed to list users."""
    factories.UserFactory.create_batch(2)
@@ -271,11 +322,13 @@ def test_api_users_retrieve_me_authenticated():
        "email": user.email,
        "full_name": user.full_name,
        "language": user.language,
+        "timezone": str(user.timezone),
        "can_access": True,
        "can_admin": True,
        "organization": {
            "id": str(user.organization.id),
            "name": user.organization.name,
+            "sharing_level": "freebusy",
        },
    }

@@ -440,8 +493,8 @@ def test_api_users_update_anonymous():

 def test_api_users_update_authenticated_self():
    """
-    Authenticated users should be able to update their own user but only "language"
-    and "timezone" fields.
+    Authenticated users should be able to update their own user but only "language",
+    "timezone" fields.
    """
    user = factories.UserFactory()

@@ -528,8 +581,8 @@ def test_api_users_patch_anonymous():

 def test_api_users_patch_authenticated_self():
    """
-    Authenticated users should be able to patch their own user but only "language"
-    and "timezone" fields.
+    Authenticated users should be able to patch their own user but only "language",
+    "timezone" fields.
    """
    user = factories.UserFactory()

--- a/src/backend/core/tests/test_caldav_proxy.py
+++ b/src/backend/core/tests/test_caldav_proxy.py
@@ -335,6 +335,232 @@ class TestCalDAVProxy:
        assert response.status_code == HTTP_400_BAD_REQUEST


+@pytest.mark.django_db
+class TestCalDAVFreeBusy:
+    """Tests for free/busy queries via CalDAV outbox POST."""
+
+    FREEBUSY_REQUEST = (
+        "BEGIN:VCALENDAR\r\n"
+        "VERSION:2.0\r\n"
+        "PRODID:-//Test//EN\r\n"
+        "METHOD:REQUEST\r\n"
+        "BEGIN:VFREEBUSY\r\n"
+        "DTSTART:20260309T000000Z\r\n"
+        "DTEND:20260310T000000Z\r\n"
+        "ORGANIZER:mailto:{organizer}\r\n"
+        "ATTENDEE:mailto:{attendee}\r\n"
+        "END:VFREEBUSY\r\n"
+        "END:VCALENDAR"
+    )
+
+    FREEBUSY_RESPONSE = (
+        '<?xml version="1.0" encoding="utf-8"?>\n'
+        '<cal:schedule-response xmlns:d="DAV:" '
+        'xmlns:cal="urn:ietf:params:xml:ns:caldav">\n'
+        "  <cal:response>\n"
+        "    <cal:recipient><d:href>mailto:{attendee}</d:href></cal:recipient>\n"
+        "    <cal:request-status>2.0;Success</cal:request-status>\n"
+        "    <cal:calendar-data>"
+        "BEGIN:VCALENDAR\r\n"
+        "VERSION:2.0\r\n"
+        "PRODID:-//SabreDAV//EN\r\n"
+        "BEGIN:VFREEBUSY\r\n"
+        "DTSTART:20260309T000000Z\r\n"
+        "DTEND:20260310T000000Z\r\n"
+        "FREEBUSY:20260309T100000Z/20260309T110000Z\r\n"
+        "END:VFREEBUSY\r\n"
+        "END:VCALENDAR"
+        "</cal:calendar-data>\n"
+        "  </cal:response>\n"
+        "</cal:schedule-response>"
+    )
+
+    @responses.activate
+    def test_freebusy_post_forwarded_with_correct_content_type(self):
+        """POST to outbox should forward text/calendar content-type to CalDAV."""
+        user = factories.UserFactory(email="alice@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        outbox_path = f"calendars/users/{user.email}/outbox/"
+        responses.add(
+            responses.Response(
+                method="POST",
+                url=f"{caldav_url}/caldav/{outbox_path}",
+                status=HTTP_200_OK,
+                body=self.FREEBUSY_RESPONSE.format(attendee="bob@example.com"),
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        body = self.FREEBUSY_REQUEST.format(
+            organizer=user.email, attendee="bob@example.com"
+        )
+        response = client.generic(
+            "POST",
+            f"/caldav/{outbox_path}",
+            data=body,
+            content_type="text/calendar; charset=utf-8",
+        )
+
+        assert response.status_code == HTTP_200_OK
+        assert len(responses.calls) == 1
+
+        # Verify content-type is forwarded (not overwritten to application/xml)
+        forwarded = responses.calls[0].request
+        assert "text/calendar" in forwarded.headers["Content-Type"]
+
+    @responses.activate
+    def test_freebusy_post_forwards_body(self):
+        """POST to outbox should forward the iCalendar body unchanged."""
+        user = factories.UserFactory(email="alice@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        outbox_path = f"calendars/users/{user.email}/outbox/"
+        responses.add(
+            responses.Response(
+                method="POST",
+                url=f"{caldav_url}/caldav/{outbox_path}",
+                status=HTTP_200_OK,
+                body=self.FREEBUSY_RESPONSE.format(attendee="bob@example.com"),
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        body = self.FREEBUSY_REQUEST.format(
+            organizer=user.email, attendee="bob@example.com"
+        )
+        client.generic(
+            "POST",
+            f"/caldav/{outbox_path}",
+            data=body,
+            content_type="text/calendar; charset=utf-8",
+        )
+
+        # Verify the body was forwarded
+        forwarded = responses.calls[0].request
+        assert b"BEGIN:VCALENDAR" in forwarded.body
+        assert b"VFREEBUSY" in forwarded.body
+        assert b"bob@example.com" in forwarded.body
+
+    @responses.activate
+    def test_freebusy_post_forwards_auth_headers(self):
+        """POST to outbox should include X-Forwarded-User and X-Api-Key."""
+        user = factories.UserFactory(email="alice@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        outbox_path = f"calendars/users/{user.email}/outbox/"
+        responses.add(
+            responses.Response(
+                method="POST",
+                url=f"{caldav_url}/caldav/{outbox_path}",
+                status=HTTP_200_OK,
+                body=self.FREEBUSY_RESPONSE.format(attendee="bob@example.com"),
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        body = self.FREEBUSY_REQUEST.format(
+            organizer=user.email, attendee="bob@example.com"
+        )
+        client.generic(
+            "POST",
+            f"/caldav/{outbox_path}",
+            data=body,
+            content_type="text/calendar; charset=utf-8",
+        )
+
+        forwarded = responses.calls[0].request
+        assert forwarded.headers["X-Forwarded-User"] == user.email
+        assert forwarded.headers["X-Api-Key"] == settings.CALDAV_OUTBOUND_API_KEY
+
+    @responses.activate
+    def test_freebusy_post_returns_schedule_response(self):
+        """POST to outbox should return the CalDAV schedule-response XML."""
+        user = factories.UserFactory(email="alice@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        outbox_path = f"calendars/users/{user.email}/outbox/"
+        response_body = self.FREEBUSY_RESPONSE.format(attendee="bob@example.com")
+        responses.add(
+            responses.Response(
+                method="POST",
+                url=f"{caldav_url}/caldav/{outbox_path}",
+                status=HTTP_200_OK,
+                body=response_body,
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        body = self.FREEBUSY_REQUEST.format(
+            organizer=user.email, attendee="bob@example.com"
+        )
+        response = client.generic(
+            "POST",
+            f"/caldav/{outbox_path}",
+            data=body,
+            content_type="text/calendar; charset=utf-8",
+        )
+
+        assert response.status_code == HTTP_200_OK
+        # Verify the schedule-response is returned to the client
+        root = ET.fromstring(response.content)
+        ns = {"cal": "urn:ietf:params:xml:ns:caldav", "d": "DAV:"}
+        status = root.find(".//cal:request-status", ns)
+        assert status is not None
+        assert "2.0" in status.text
+
+    def test_freebusy_post_requires_authentication(self):
+        """POST to outbox should require authentication."""
+        client = APIClient()
+        response = client.generic(
+            "POST",
+            "/caldav/calendars/users/alice@example.com/outbox/",
+            data="BEGIN:VCALENDAR\r\nEND:VCALENDAR",
+            content_type="text/calendar",
+        )
+        assert response.status_code == HTTP_401_UNAUTHORIZED
+
+    @responses.activate
+    def test_freebusy_post_includes_organization_header(self):
+        """POST to outbox should include X-CalDAV-Organization header."""
+        user = factories.UserFactory(email="alice@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        outbox_path = f"calendars/users/{user.email}/outbox/"
+        responses.add(
+            responses.Response(
+                method="POST",
+                url=f"{caldav_url}/caldav/{outbox_path}",
+                status=HTTP_200_OK,
+                body=self.FREEBUSY_RESPONSE.format(attendee="bob@example.com"),
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        body = self.FREEBUSY_REQUEST.format(
+            organizer=user.email, attendee="bob@example.com"
+        )
+        client.generic(
+            "POST",
+            f"/caldav/{outbox_path}",
+            data=body,
+            content_type="text/calendar; charset=utf-8",
+        )
+
+        forwarded = responses.calls[0].request
+        assert forwarded.headers["X-CalDAV-Organization"] == str(user.organization_id)
+
+
 class TestValidateCaldavProxyPath:
    """Tests for validate_caldav_proxy_path utility."""

--- a/src/backend/core/tests/test_organizations.py
+++ b/src/backend/core/tests/test_organizations.py
@@ -194,3 +194,100 @@ def test_user_list_same_org_visible():
    assert len(data) == 1
    assert data[0]["email"] == "carol@example.com"
    get_entitlements_backend.cache_clear()
+
+
+# -- Sharing level --
+
+
+@pytest.mark.django_db
+def test_effective_sharing_level_defaults_to_server_setting():
+    """Organization without override returns server-wide default."""
+    org = factories.OrganizationFactory(default_sharing_level=None)
+    assert org.effective_sharing_level == "freebusy"
+
+
+@pytest.mark.django_db
+@override_settings(ORG_DEFAULT_SHARING_LEVEL="none")
+def test_effective_sharing_level_follows_server_override():
+    """Organization without override returns overridden server default."""
+    org = factories.OrganizationFactory(default_sharing_level=None)
+    assert org.effective_sharing_level == "none"
+
+
+@pytest.mark.django_db
+def test_effective_sharing_level_org_override():
+    """Organization with explicit level ignores server default."""
+    org = factories.OrganizationFactory(default_sharing_level="read")
+    assert org.effective_sharing_level == "read"
+
+
+# -- Organization settings API --
+
+
+@pytest.mark.django_db
+@override_settings(
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_org_settings_retrieve():
+    """GET /organization-settings/current/ returns org sharing level."""
+    get_entitlements_backend.cache_clear()
+    org = factories.OrganizationFactory(external_id="test-org")
+    user = factories.UserFactory(organization=org)
+
+    client = APIClient()
+    client.force_authenticate(user=user)
+    response = client.get("/api/v1.0/organization-settings/current/")
+
+    assert response.status_code == HTTP_200_OK
+    assert response.json()["sharing_level"] == "freebusy"
+    get_entitlements_backend.cache_clear()
+
+
+@pytest.mark.django_db
+@override_settings(
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_org_settings_update_sharing_level():
+    """PATCH /organization-settings/current/ updates sharing level."""
+    get_entitlements_backend.cache_clear()
+    org = factories.OrganizationFactory(external_id="test-org")
+    user = factories.UserFactory(organization=org)
+
+    client = APIClient()
+    client.force_authenticate(user=user)
+    response = client.patch(
+        "/api/v1.0/organization-settings/current/",
+        {"default_sharing_level": "none"},
+        format="json",
+    )
+
+    assert response.status_code == HTTP_200_OK
+    org.refresh_from_db()
+    assert org.default_sharing_level == "none"
+    assert response.json()["sharing_level"] == "none"
+    get_entitlements_backend.cache_clear()
+
+
+@pytest.mark.django_db
+@override_settings(
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_org_settings_update_rejects_invalid_level():
+    """PATCH with invalid sharing level returns 400."""
+    get_entitlements_backend.cache_clear()
+    org = factories.OrganizationFactory(external_id="test-org")
+    user = factories.UserFactory(organization=org)
+
+    client = APIClient()
+    client.force_authenticate(user=user)
+    response = client.patch(
+        "/api/v1.0/organization-settings/current/",
+        {"default_sharing_level": "superadmin"},
+        format="json",
+    )
+
+    assert response.status_code == 400
+    get_entitlements_backend.cache_clear()
--- a/src/backend/core/tests/test_permissions_security.py
+++ b/src/backend/core/tests/test_permissions_security.py
@@ -272,6 +272,34 @@ class TestCalDAVProxyOrgHeader:
        assert request.headers["X-CalDAV-Organization"] == str(org.id)
        assert request.headers["X-CalDAV-Organization"] != "spoofed-org-id"

+    @responses.activate
+    def test_proxy_sends_sharing_level_header(self):
+        """CalDAV proxy sends X-CalDAV-Sharing-Level from org's effective level."""
+        org = factories.OrganizationFactory(
+            external_id="org-fb", default_sharing_level="none"
+        )
+        user = factories.UserFactory(email="alice@example.com", organization=org)
+
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        responses.add(
+            responses.Response(
+                method="PROPFIND",
+                url=f"{caldav_url}/caldav/principals/resources/",
+                status=HTTP_207_MULTI_STATUS,
+                body='<?xml version="1.0"?><multistatus xmlns="DAV:"></multistatus>',
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        client.generic("PROPFIND", "/caldav/principals/resources/")
+
+        assert len(responses.calls) == 1
+        request = responses.calls[0].request
+        assert request.headers["X-CalDAV-Sharing-Level"] == "none"
+

 # ---------------------------------------------------------------------------
 # IsEntitledToAccess permission — fail-closed
--- a/src/backend/core/urls.py
+++ b/src/backend/core/urls.py
@@ -20,6 +20,11 @@ router.register("users", viewsets.UserViewSet, basename="users")
 router.register("calendars", viewsets.CalendarViewSet, basename="calendars")
 router.register("resources", viewsets.ResourceViewSet, basename="resources")
 router.register("channels", ChannelViewSet, basename="channels")
+router.register(
+    "organization-settings",
+    viewsets.OrganizationSettingsViewSet,
+    basename="organization-settings",
+)

 urlpatterns = [
    path(
--- a/src/caldav/server.php
+++ b/src/caldav/server.php
@@ -17,6 +17,8 @@ use Calendars\SabreDav\AttendeeNormalizerPlugin;
 use Calendars\SabreDav\InternalApiPlugin;
 use Calendars\SabreDav\ResourceAutoSchedulePlugin;
 use Calendars\SabreDav\ResourceMkCalendarBlockPlugin;
+use Calendars\SabreDav\FreeBusyOrgScopePlugin;
+use Calendars\SabreDav\AvailabilityPlugin;
 use Calendars\SabreDav\CalendarsRoot;
 use Calendars\SabreDav\CustomCalDAVPlugin;
 use Calendars\SabreDav\PrincipalsRoot;
@@ -88,7 +90,12 @@ $principalBackend->setServer($server);
 $server->addPlugin($authPlugin);
 $server->addPlugin(new CustomCalDAVPlugin());
 $server->addPlugin(new CardDAV\Plugin());
-$server->addPlugin(new DAVACL\Plugin());
+// PrincipalsRoot is a plain DAV\Collection (not IPrincipalCollection), so the
+// default principalCollectionSet ['principals'] would skip it during principal
+// search. Point directly to the child IPrincipalCollection nodes instead.
+$aclPlugin = new DAVACL\Plugin();
+$aclPlugin->principalCollectionSet = ['principals/users', 'principals/resources'];
+$server->addPlugin($aclPlugin);
 $server->addPlugin(new DAV\Browser\Plugin());

 // Add ICS export plugin for iCal subscription URLs
@@ -169,6 +176,10 @@ if ($defaultCallbackUrl) {
 $imipPlugin = new HttpCallbackIMipPlugin($callbackApiKey, $defaultCallbackUrl);
 $server->addPlugin($imipPlugin);

+// Enforce org-level freebusy sharing settings
+// Blocks VFREEBUSY queries when X-CalDAV-Sharing-Level is "none"
+$server->addPlugin(new FreeBusyOrgScopePlugin());
+
 // Add CalDAV scheduling support
 // See https://sabre.io/dav/scheduling/
 // The Schedule\Plugin will automatically find and use the IMipPlugin we just added
@@ -183,6 +194,10 @@ $server->addPlugin(new ResourceAutoSchedulePlugin($pdo, $caldavBackend));
 // Block MKCALENDAR on resource principals (each resource has exactly one calendar)
 $server->addPlugin(new ResourceMkCalendarBlockPlugin());

+// Add availability integration for freebusy responses
+// Reads calendar-availability property and adds BUSY-UNAVAILABLE periods
+$server->addPlugin(new AvailabilityPlugin());
+
 // Add property storage plugin for custom properties (resource metadata, etc.)
 $server->addPlugin(new DAV\PropertyStorage\Plugin(
    new DAV\PropertyStorage\Backend\PDO($pdo)
--- a/src/caldav/src/AvailabilityPlugin.php
+++ b/src/caldav/src/AvailabilityPlugin.php
@@ -0,0 +1,513 @@
+<?php
+/**
+ * AvailabilityPlugin - Integrates VAVAILABILITY (RFC 7953) into freebusy responses.
+ *
+ * When a freebusy query is made via the scheduling outbox, this plugin
+ * post-processes the response to add BUSY-UNAVAILABLE periods based on
+ * each recipient's calendar-availability property.
+ *
+ * The calendar-availability property is stored on the user's calendar home
+ * via the PropertyStorage plugin and contains a VCALENDAR with VAVAILABILITY
+ * and AVAILABLE components that define working hours.
+ *
+ * Runs after Schedule\Plugin (priority 200 on afterMethod:POST).
+ */
+
+namespace Calendars\SabreDav;
+
+use Sabre\DAV;
+use Sabre\DAV\Server;
+use Sabre\DAV\ServerPlugin;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+use Sabre\VObject\Reader;
+
+class AvailabilityPlugin extends ServerPlugin
+{
+    /** @var Server */
+    protected $server;
+
+    /** CalDAV namespace */
+    private const CALDAV_NS = '{urn:ietf:params:xml:ns:caldav}';
+
+    /** calendar-availability property name */
+    private const AVAILABILITY_PROP = '{urn:ietf:params:xml:ns:caldav}calendar-availability';
+
+    public function initialize(Server $server)
+    {
+        $this->server = $server;
+        // Priority 200: runs after Schedule\Plugin (110) has built the response
+        $server->on('afterMethod:POST', [$this, 'afterPost'], 200);
+    }
+
+    /**
+     * Post-process scheduling outbox responses to inject BUSY-UNAVAILABLE periods.
+     */
+    public function afterPost(RequestInterface $request, ResponseInterface $response)
+    {
+        // Only process successful responses
+        if ($response->getStatus() !== 200) {
+            return;
+        }
+
+        // Only process outbox requests
+        $path = $request->getPath();
+        if (strpos($path, 'outbox') === false) {
+            return;
+        }
+
+        // Only process XML responses
+        $contentType = $response->getHeader('Content-Type');
+        if (!$contentType || strpos($contentType, 'application/xml') === false) {
+            return;
+        }
+
+        $body = $response->getBodyAsString();
+        if (!$body) {
+            return;
+        }
+
+        try {
+            $modified = $this->processScheduleResponse($body);
+            if ($modified !== null) {
+                $response->setBody($modified);
+            }
+        } catch (\Exception $e) {
+            error_log("[AvailabilityPlugin] Error processing response: " . $e->getMessage());
+        }
+    }
+
+    /**
+     * Parse the schedule-response XML and inject BUSY-UNAVAILABLE periods
+     * for each recipient that has a calendar-availability property.
+     *
+     * @param string $xml The original XML response body
+     * @return string|null Modified XML or null if no changes
+     */
+    private function processScheduleResponse($xml)
+    {
+        $dom = new \DOMDocument();
+        $dom->preserveWhiteSpace = true;
+        $dom->formatOutput = false;
+
+        if (!@$dom->loadXML($xml)) {
+            error_log("[AvailabilityPlugin] Failed to parse XML response");
+            return null;
+        }
+
+        $xpath = new \DOMXPath($dom);
+        $xpath->registerNamespace('D', 'DAV:');
+        $xpath->registerNamespace('C', 'urn:ietf:params:xml:ns:caldav');
+
+        // Find all schedule-response/response elements
+        $responses = $xpath->query('//C:schedule-response/C:response');
+        if (!$responses || $responses->length === 0) {
+            return null;
+        }
+
+        $modified = false;
+
+        foreach ($responses as $responseNode) {
+            // Extract recipient email
+            $recipientNodes = $xpath->query('.//C:recipient/D:href', $responseNode);
+            if (!$recipientNodes || $recipientNodes->length === 0) {
+                continue;
+            }
+            $recipientHref = $recipientNodes->item(0)->textContent;
+            $email = $this->extractEmail($recipientHref);
+            if (!$email) {
+                continue;
+            }
+
+            // Find calendar-data element
+            $calDataNodes = $xpath->query('.//C:calendar-data', $responseNode);
+            if (!$calDataNodes || $calDataNodes->length === 0) {
+                continue;
+            }
+            $calDataNode = $calDataNodes->item(0);
+            $icsData = $calDataNode->textContent;
+
+            if (strpos($icsData, 'VFREEBUSY') === false) {
+                continue;
+            }
+
+            // Get the user's availability property
+            $availability = $this->getCalendarAvailability($email);
+            if (!$availability) {
+                continue;
+            }
+
+            // Parse available windows from the VAVAILABILITY
+            $availableWindows = $this->parseAvailableWindows($availability);
+            if (empty($availableWindows)) {
+                continue;
+            }
+
+            // Extract the freebusy query range from the VFREEBUSY component
+            $queryRange = $this->extractFreebusyRange($icsData);
+            if (!$queryRange) {
+                continue;
+            }
+
+            // Compute BUSY-UNAVAILABLE periods
+            $busyPeriods = $this->computeBusyUnavailable(
+                $queryRange['start'],
+                $queryRange['end'],
+                $availableWindows
+            );
+
+            if (empty($busyPeriods)) {
+                continue;
+            }
+
+            // Inject BUSY-UNAVAILABLE lines into the ICS data
+            $modifiedIcs = $this->injectBusyUnavailable($icsData, $busyPeriods);
+            if ($modifiedIcs !== null) {
+                $calDataNode->textContent = '';
+                $calDataNode->appendChild($dom->createTextNode($modifiedIcs));
+                $modified = true;
+            }
+        }
+
+        if ($modified) {
+            return $dom->saveXML();
+        }
+
+        return null;
+    }
+
+    /**
+     * Extract email from a mailto: URI.
+     *
+     * @param string $uri
+     * @return string|null
+     */
+    private function extractEmail($uri)
+    {
+        if (stripos($uri, 'mailto:') === 0) {
+            return strtolower(substr($uri, 7));
+        }
+        return null;
+    }
+
+    /**
+     * Get the calendar-availability property for a user.
+     *
+     * Resolves the calendar home path from the principal URI via the
+     * CalDAV plugin rather than hardcoding the path structure.
+     *
+     * @param string $email
+     * @return string|null The VCALENDAR string or null
+     */
+    private function getCalendarAvailability($email)
+    {
+        $caldavPlugin = $this->server->getPlugin('caldav');
+        if (!$caldavPlugin) {
+            return null;
+        }
+
+        $principalUri = 'principals/users/' . $email;
+        $calendarHomePath = $caldavPlugin->getCalendarHomeForPrincipal($principalUri);
+        if (!$calendarHomePath) {
+            return null;
+        }
+
+        try {
+            $properties = $this->server->getProperties(
+                $calendarHomePath,
+                [self::AVAILABILITY_PROP]
+            );
+
+            if (isset($properties[self::AVAILABILITY_PROP])) {
+                return $properties[self::AVAILABILITY_PROP];
+            }
+        } catch (\Exception $e) {
+            error_log("[AvailabilityPlugin] Failed to get availability for user: "
+                . $e->getMessage());
+        }
+
+        return null;
+    }
+
+    /**
+     * Parse VAVAILABILITY/AVAILABLE components to extract available windows.
+     *
+     * Returns an array of available window definitions, each with:
+     * - 'startTime': time string "HH:MM:SS"
+     * - 'endTime': time string "HH:MM:SS"
+     * - 'days': array of day-of-week integers (1=Monday .. 7=Sunday, ISO-8601)
+     * - 'specificDate': string "Y-m-d" if this is a specific-date window (no RRULE)
+     *
+     * @param string $vcalendarStr
+     * @return array
+     */
+    private function parseAvailableWindows($vcalendarStr)
+    {
+        $windows = [];
+
+        try {
+            $vcalendar = Reader::read($vcalendarStr);
+        } catch (\Exception $e) {
+            error_log("[AvailabilityPlugin] Failed to parse VAVAILABILITY: " . $e->getMessage());
+            return $windows;
+        }
+
+        if (!isset($vcalendar->VAVAILABILITY)) {
+            return $windows;
+        }
+
+        foreach ($vcalendar->VAVAILABILITY as $vavailability) {
+            if (!isset($vavailability->AVAILABLE)) {
+                continue;
+            }
+
+            foreach ($vavailability->AVAILABLE as $available) {
+                if (!isset($available->DTSTART) || !isset($available->DTEND)) {
+                    continue;
+                }
+
+                $dtstart = $available->DTSTART->getDateTime();
+                $dtend = $available->DTEND->getDateTime();
+
+                $startTime = $dtstart->format('H:i:s');
+                $endTime = $dtend->format('H:i:s');
+
+                // Parse RRULE to get BYDAY
+                $days = [];
+                $specificDate = null;
+                if (isset($available->RRULE)) {
+                    $rrule = (string)$available->RRULE;
+                    if (preg_match('/BYDAY=([A-Z,]+)/', $rrule, $matches)) {
+                        $dayMap = [
+                            'MO' => 1,
+                            'TU' => 2,
+                            'WE' => 3,
+                            'TH' => 4,
+                            'FR' => 5,
+                            'SA' => 6,
+                            'SU' => 7,
+                        ];
+                        foreach (explode(',', $matches[1]) as $day) {
+                            if (isset($dayMap[$day])) {
+                                $days[] = $dayMap[$day];
+                            }
+                        }
+                    }
+                } else {
+                    // No RRULE: specific-date availability, scoped to DTSTART date
+                    $specificDate = $dtstart->format('Y-m-d');
+                    $days = [(int)$dtstart->format('N')];
+                }
+
+                $windows[] = [
+                    'startTime' => $startTime,
+                    'endTime' => $endTime,
+                    'days' => $days,
+                    'specificDate' => $specificDate,
+                ];
+            }
+        }
+
+        return $windows;
+    }
+
+    /**
+     * Extract the DTSTART and DTEND range from a VFREEBUSY component.
+     *
+     * @param string $icsData
+     * @return array|null ['start' => DateTimeImmutable, 'end' => DateTimeImmutable]
+     */
+    private function extractFreebusyRange($icsData)
+    {
+        try {
+            $vcalendar = Reader::read($icsData);
+        } catch (\Exception $e) {
+            error_log("[AvailabilityPlugin] Failed to parse VFREEBUSY ICS: " . $e->getMessage());
+            return null;
+        }
+
+        if (!isset($vcalendar->VFREEBUSY)) {
+            return null;
+        }
+
+        $vfreebusy = $vcalendar->VFREEBUSY;
+
+        if (!isset($vfreebusy->DTSTART) || !isset($vfreebusy->DTEND)) {
+            return null;
+        }
+
+        return [
+            'start' => $vfreebusy->DTSTART->getDateTime(),
+            'end' => $vfreebusy->DTEND->getDateTime(),
+        ];
+    }
+
+    /**
+     * Compute BUSY-UNAVAILABLE periods for times outside available windows.
+     *
+     * TODO: The available times in DTSTART/DTEND of AVAILABLE are treated as
+     * UTC for now. Proper timezone handling would require resolving the TZID
+     * from the VAVAILABILITY component and converting accordingly.
+     *
+     * @param \DateTimeInterface $rangeStart
+     * @param \DateTimeInterface $rangeEnd
+     * @param array $windows Available windows from parseAvailableWindows()
+     * @return array Array of ['start' => DateTimeImmutable, 'end' => DateTimeImmutable]
+     */
+    private function computeBusyUnavailable(
+        \DateTimeInterface $rangeStart,
+        \DateTimeInterface $rangeEnd,
+        array $windows
+    ) {
+        $utc = new \DateTimeZone('UTC');
+        $busyPeriods = [];
+
+        // Iterate day by day through the range
+        $currentDay = new \DateTimeImmutable(
+            $rangeStart->format('Y-m-d'),
+            $utc
+        );
+        $endDay = new \DateTimeImmutable(
+            $rangeEnd->format('Y-m-d'),
+            $utc
+        );
+
+        while ($currentDay <= $endDay) {
+            $dayOfWeek = (int)$currentDay->format('N'); // 1=Monday .. 7=Sunday
+            $dayStart = $currentDay;
+            $dayEnd = $currentDay->modify('+1 day');
+
+            // Clamp to the query range
+            $effectiveDayStart = $dayStart < $rangeStart
+                ? new \DateTimeImmutable($rangeStart->format('Y-m-d\TH:i:s'), $utc)
+                : $dayStart;
+            $effectiveDayEnd = $dayEnd > $rangeEnd
+                ? new \DateTimeImmutable($rangeEnd->format('Y-m-d\TH:i:s'), $utc)
+                : $dayEnd;
+
+            if ($effectiveDayStart >= $effectiveDayEnd) {
+                $currentDay = $currentDay->modify('+1 day');
+                continue;
+            }
+
+            // Collect available slots for this day of the week
+            $availableSlots = [];
+            $dateStr = $currentDay->format('Y-m-d');
+            foreach ($windows as $window) {
+                // Skip specific-date windows that don't match this day
+                if ($window['specificDate'] !== null && $window['specificDate'] !== $dateStr) {
+                    continue;
+                }
+                if (in_array($dayOfWeek, $window['days'], true)) {
+                    $slotStart = new \DateTimeImmutable(
+                        $currentDay->format('Y-m-d') . 'T' . $window['startTime'],
+                        $utc
+                    );
+                    $slotEnd = new \DateTimeImmutable(
+                        $currentDay->format('Y-m-d') . 'T' . $window['endTime'],
+                        $utc
+                    );
+
+                    // Clamp to effective day range
+                    if ($slotStart < $effectiveDayStart) {
+                        $slotStart = $effectiveDayStart;
+                    }
+                    if ($slotEnd > $effectiveDayEnd) {
+                        $slotEnd = $effectiveDayEnd;
+                    }
+
+                    if ($slotStart < $slotEnd) {
+                        $availableSlots[] = [
+                            'start' => $slotStart,
+                            'end' => $slotEnd,
+                        ];
+                    }
+                }
+            }
+
+            // Sort available slots by start time
+            usort($availableSlots, function ($a, $b) {
+                return $a['start'] <=> $b['start'];
+            });
+
+            // Merge overlapping slots
+            $mergedSlots = [];
+            foreach ($availableSlots as $slot) {
+                if (empty($mergedSlots)) {
+                    $mergedSlots[] = $slot;
+                } else {
+                    $last = &$mergedSlots[count($mergedSlots) - 1];
+                    if ($slot['start'] <= $last['end']) {
+                        if ($slot['end'] > $last['end']) {
+                            $last['end'] = $slot['end'];
+                        }
+                    } else {
+                        $mergedSlots[] = $slot;
+                    }
+                    unset($last);
+                }
+            }
+
+            // Compute gaps (BUSY-UNAVAILABLE periods)
+            $cursor = $effectiveDayStart;
+            foreach ($mergedSlots as $slot) {
+                if ($cursor < $slot['start']) {
+                    $busyPeriods[] = [
+                        'start' => $cursor,
+                        'end' => $slot['start'],
+                    ];
+                }
+                $cursor = $slot['end'];
+            }
+            if ($cursor < $effectiveDayEnd) {
+                $busyPeriods[] = [
+                    'start' => $cursor,
+                    'end' => $effectiveDayEnd,
+                ];
+            }
+
+            $currentDay = $currentDay->modify('+1 day');
+        }
+
+        return $busyPeriods;
+    }
+
+    /**
+     * Inject FREEBUSY;FBTYPE=BUSY-UNAVAILABLE lines into a VFREEBUSY ICS string.
+     *
+     * @param string $icsData
+     * @param array $busyPeriods
+     * @return string|null Modified ICS data or null if injection failed
+     */
+    private function injectBusyUnavailable($icsData, array $busyPeriods)
+    {
+        // Build FREEBUSY lines
+        $lines = '';
+        foreach ($busyPeriods as $period) {
+            $start = $period['start']->format('Ymd\THis\Z');
+            $end = $period['end']->format('Ymd\THis\Z');
+            $lines .= "FREEBUSY;FBTYPE=BUSY-UNAVAILABLE:{$start}/{$end}\r\n";
+        }
+
+        // Insert before END:VFREEBUSY
+        $pos = strpos($icsData, "END:VFREEBUSY");
+        if ($pos === false) {
+            return null;
+        }
+
+        return substr($icsData, 0, $pos) . $lines . substr($icsData, $pos);
+    }
+
+    public function getPluginName()
+    {
+        return 'availability';
+    }
+
+    public function getPluginInfo()
+    {
+        return [
+            'name' => $this->getPluginName(),
+            'description' => 'Integrates VAVAILABILITY (RFC 7953) into freebusy responses',
+        ];
+    }
+}
--- a/src/caldav/src/FreeBusyOrgScopePlugin.php
+++ b/src/caldav/src/FreeBusyOrgScopePlugin.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Calendars\SabreDav;
+
+use Sabre\DAV;
+use Sabre\HTTP\RequestInterface;
+
+/**
+ * Blocks VFREEBUSY queries when the organization sharing level is "none".
+ *
+ * The X-CalDAV-Sharing-Level header is set by the Django proxy based on
+ * the organization's effective sharing level setting.
+ *
+ * Regular scheduling requests (invitations) are not affected.
+ */
+class FreeBusyOrgScopePlugin extends DAV\ServerPlugin
+{
+    protected $server;
+
+    public function initialize(DAV\Server $server)
+    {
+        $this->server = $server;
+        // Priority 99: before Schedule\Plugin (110) processes freebusy
+        $server->on('beforeMethod:POST', [$this, 'beforePost'], 99);
+    }
+
+    /**
+     * Intercept POST to scheduling outbox and block VFREEBUSY if sharing is "none".
+     */
+    public function beforePost(RequestInterface $request)
+    {
+        $path = $request->getPath();
+
+        // Only intercept outbox requests (where freebusy queries are sent)
+        if (strpos($path, '/outbox') === false) {
+            return;
+        }
+
+        $sharingLevel = $request->getHeader('X-CalDAV-Sharing-Level');
+
+        // Only block when sharing is explicitly disabled
+        if ($sharingLevel !== 'none') {
+            return;
+        }
+
+        // Read body to check if this is a VFREEBUSY request
+        $body = $request->getBodyAsString();
+        $request->setBody($body); // Reset stream for subsequent reads
+
+        if (stripos($body, 'VFREEBUSY') !== false) {
+            throw new DAV\Exception\Forbidden(
+                'Free/busy queries are not allowed when organization sharing is disabled'
+            );
+        }
+    }
+
+    public function getPluginName()
+    {
+        return 'freebusy-org-scope';
+    }
+
+    public function getPluginInfo()
+    {
+        return [
+            'name' => $this->getPluginName(),
+            'description' => 'Enforces organization-level freebusy sharing settings',
+        ];
+    }
+}
--- a/src/caldav/src/PrincipalsRoot.php
+++ b/src/caldav/src/PrincipalsRoot.php
@@ -77,29 +77,46 @@ class NamedPrincipalCollection extends CalDAV\Principal\Collection
    {
        return $this->nodeName;
    }
+
+    /**
+     * Return SchedulablePrincipal nodes that allow authenticated users to
+     * read principal properties (required for CalDAV scheduling / freebusy).
+     */
+    public function getChildForPrincipal(array $principal)
+    {
+        return new SchedulablePrincipal($this->principalBackend, $principal);
+    }
 }

 /**
- * Principal collection for resources that returns ResourcePrincipal nodes.
+ * Principal collection for resources.
 *
 * Resource principals have no DAV owner, so the default ACL (which only
 * grants {DAV:}all to {DAV:}owner) blocks all property reads with 403.
- * This collection returns ResourcePrincipal nodes that additionally grant
- * {DAV:}read to {DAV:}authenticated, allowing any logged-in user to
- * discover resource names, types, and emails via PROPFIND.
+ * This collection returns SchedulablePrincipal nodes that additionally grant
+ * {DAV:}read to {DAV:}authenticated.
 */
 class ResourcePrincipalCollection extends NamedPrincipalCollection
 {
    public function getChildForPrincipal(array $principal)
    {
-        return new ResourcePrincipal($this->principalBackend, $principal);
+        return new SchedulablePrincipal($this->principalBackend, $principal);
    }
 }

 /**
- * A principal node with a permissive read ACL for resource discovery.
+ * A principal node with read ACL for authenticated users.
+ *
+ * Required for CalDAV scheduling: the Schedule\Plugin looks up other users'
+ * calendar-home-set and schedule-inbox-URL via principalSearch(), which
+ * triggers a propFind that is subject to ACL. Without read access, the
+ * properties return 403 and freebusy queries fail with "Could not find
+ * calendar-home-set".
+ *
+ * Also used for resource discovery (any logged-in user can discover resource
+ * names, types, and emails via PROPFIND).
 */
-class ResourcePrincipal extends CalDAV\Principal\User
+class SchedulablePrincipal extends CalDAV\Principal\User
 {
    public function getACL()
    {
--- a/src/frontend/apps/calendars/src/features/calendar/api.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/api.ts
@@ -140,11 +140,7 @@ interface ImportTaskResponse {
 */
 export interface TaskStatus {
  status: "PENDING" | "PROGRESS" | "SUCCESS" | "FAILURE";
-  result: {
-    status: string;
-    result: ImportEventsResult | null;
-    error: string | null;
-  } | null;
+  result: ImportEventsResult | null;
  error: string | null;
  progress?: number;
  message?: string;
@@ -202,14 +198,14 @@ export const pollImportTask = async (
          return;
        }

-        if (status.status === "SUCCESS" && status.result?.result) {
-          resolve(status.result.result);
+        if (status.status === "SUCCESS" && status.result) {
+          resolve(status.result);
          return;
        }

        reject(
          new Error(
-            status.result?.error ?? status.error ?? "Import failed",
+            status.error ?? "Import failed",
          ),
        );
      } catch (error) {
--- a/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/CalendarModal.tsx
+++ b/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/CalendarModal.tsx
@@ -10,7 +10,6 @@ import {
  Input,
  Modal,
  ModalSize,
-  TextArea,
 } from "@gouvfr-lasuite/cunningham-react";

 import { DEFAULT_COLORS } from "./constants";
@@ -26,7 +25,6 @@ export const CalendarModal = ({
  const { t } = useTranslation();
  const [name, setName] = useState("");
  const [color, setColor] = useState(DEFAULT_COLORS[0]);
-  const [description, setDescription] = useState("");
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

@@ -36,11 +34,9 @@ export const CalendarModal = ({
      if (mode === "edit" && calendar) {
        setName(calendar.displayName || "");
        setColor(calendar.color || DEFAULT_COLORS[0]);
-        setDescription(calendar.description || "");
      } else {
        setName("");
        setColor(DEFAULT_COLORS[0]);
-        setDescription("");
      }
      setError(null);
    }
@@ -55,7 +51,7 @@ export const CalendarModal = ({
    setIsLoading(true);
    setError(null);
    try {
-      await onSave(name.trim(), color, description.trim() || undefined);
+      await onSave(name.trim(), color);
      onClose();
    } catch (err) {
      setError(err instanceof Error ? err.message : t('api.error.unexpected'));
@@ -67,7 +63,6 @@ export const CalendarModal = ({
  const handleClose = () => {
    setName("");
    setColor(DEFAULT_COLORS[0]);
-    setDescription("");
    setError(null);
    onClose();
  };
@@ -133,13 +128,6 @@ export const CalendarModal = ({
          </div>
        </div>

-        <TextArea
-          label={t('calendar.createCalendar.description')}
-          value={description}
-          onChange={(e) => setDescription(e.target.value)}
-          rows={2}
-          fullWidth
-        />
      </div>
    </Modal>
  );
--- a/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/CalendarShareModal.tsx
+++ b/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/CalendarShareModal.tsx
@@ -3,7 +3,7 @@
 * Wraps the UI Kit ShareModal for managing calendar sharing via CalDAV.
 */

-import { useState, useEffect, useCallback } from "react";
+import { useState, useEffect, useCallback, useRef } from "react";
 import { useTranslation } from "react-i18next";
 import { ShareModal } from "@gouvfr-lasuite/ui-kit";

@@ -14,6 +14,7 @@ import {
  ToasterItem,
 } from "../../../ui/components/toaster/Toaster";
 import type { CalDavCalendar } from "../../services/dav/types/caldav-service";
+import { fetchAPI } from "@/features/api/fetchApi";

 interface CalendarShareModalProps {
  isOpen: boolean;
@@ -100,16 +101,67 @@ export const CalendarShareModal = ({
    }
  }, [isOpen, calendar, fetchSharees]);

-  const handleSearchUsers = useCallback((query: string) => {
-    if (EMAIL_REGEX.test(query.trim())) {
-      const email = query.trim();
-      setSearchResults([
-        { id: email, email, full_name: email },
-      ]);
-    } else {
-      setSearchResults([]);
-    }
-  }, []);
+  const searchTimerRef = useRef<ReturnType<typeof setTimeout>>(undefined);
+
+  const handleSearchUsers = useCallback(
+    (query: string) => {
+      clearTimeout(searchTimerRef.current);
+      const trimmed = query.trim();
+
+      if (trimmed.length < 3) {
+        // For very short queries, fall back to email-only matching
+        if (EMAIL_REGEX.test(trimmed)) {
+          setSearchResults([
+            { id: trimmed, email: trimmed, full_name: trimmed },
+          ]);
+        } else {
+          setSearchResults([]);
+        }
+        return;
+      }
+
+      // Debounce the API call
+      searchTimerRef.current = setTimeout(async () => {
+        try {
+          const response = await fetchAPI("users/", {
+            params: { q: trimmed },
+          });
+          const data = await response.json();
+          const results: ShareUser[] = (data.results ?? []).map(
+            (u: { id: string; email: string; full_name: string }) => ({
+              id: u.id,
+              email: u.email,
+              full_name: u.full_name || u.email,
+            }),
+          );
+          // Always allow raw email entry too
+          if (
+            EMAIL_REGEX.test(trimmed) &&
+            !results.some(
+              (r) => r.email.toLowerCase() === trimmed.toLowerCase(),
+            )
+          ) {
+            results.push({
+              id: trimmed,
+              email: trimmed,
+              full_name: trimmed,
+            });
+          }
+          setSearchResults(results);
+        } catch {
+          // Fallback to email-only on API error
+          if (EMAIL_REGEX.test(trimmed)) {
+            setSearchResults([
+              { id: trimmed, email: trimmed, full_name: trimmed },
+            ]);
+          } else {
+            setSearchResults([]);
+          }
+        }
+      }, 300);
+    },
+    [],
+  );

  const handleInviteUser = useCallback(
    async (users: ShareUser[]) => {
--- a/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/hooks/useCalendarListState.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/hooks/useCalendarListState.ts
@@ -76,12 +76,11 @@ export const useCalendarListState = ({
  }, []);

  const handleSaveCalendar = useCallback(
-    async (name: string, color: string, description?: string) => {
+    async (name: string, color: string) => {
      if (modalState.mode === "create") {
        const result = await createCalendar({
          displayName: name,
          color,
-          description,
          components: ['VEVENT'],
        });
        if (!result.success) {
@@ -91,7 +90,6 @@ export const useCalendarListState = ({
        const result = await updateCalendar(modalState.calendar.url, {
          displayName: name,
          color,
-          description,
        });
        if (!result.success) {
          throw new Error(result.error);
--- a/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/types.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/calendar-list/types.ts
@@ -12,7 +12,7 @@ export interface CalendarModalProps {
  mode: "create" | "edit";
  calendar?: CalDavCalendar | null;
  onClose: () => void;
-  onSave: (name: string, color: string, description?: string) => Promise<void>;
+  onSave: (name: string, color: string) => Promise<void>;
 }

 /**
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/AttendeesInput.scss
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/AttendeesInput.scss
@@ -8,6 +8,7 @@
    align-items: flex-start;
    gap: 0.5rem;
    width: 100%;
+    position: relative;
  }

  &__add-btn {
@@ -37,6 +38,58 @@
    }
  }

+  &__suggestions {
+    position: absolute;
+    top: 100%;
+    left: 0;
+    right: 0;
+    z-index: 10;
+    margin: 0;
+    padding: 0.25rem 0;
+    list-style: none;
+    background: var(--c--theme--colors--greyscale-000, #fff);
+    border: 1px solid var(--c--theme--colors--greyscale-200);
+    border-radius: 4px;
+    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
+    max-height: 200px;
+    overflow-y: auto;
+  }
+
+  &__suggestion {
+    display: flex;
+    flex-direction: column;
+    gap: 0.125rem;
+    padding: 0.5rem 0.75rem;
+    cursor: pointer;
+    transition: background-color 0.1s;
+
+    &:hover,
+    &--highlighted {
+      background-color: var(--c--theme--colors--greyscale-100);
+    }
+
+    &--empty {
+      color: var(--c--theme--colors--greyscale-500);
+      font-style: italic;
+      cursor: default;
+
+      &:hover {
+        background-color: transparent;
+      }
+    }
+  }
+
+  &__suggestion-name {
+    font-size: 0.875rem;
+    font-weight: 500;
+    color: var(--c--theme--colors--greyscale-900);
+  }
+
+  &__suggestion-email {
+    font-size: 0.75rem;
+    color: var(--c--theme--colors--greyscale-500);
+  }
+
  &__pills {
    display: flex;
    flex-wrap: wrap;
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/AttendeesInput.tsx
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/AttendeesInput.tsx
@@ -1,8 +1,19 @@
-import { useState, useCallback, type KeyboardEvent } from "react";
+import {
+  useState,
+  useCallback,
+  useRef,
+  useEffect,
+  type KeyboardEvent,
+} from "react";
 import { Input } from "@gouvfr-lasuite/cunningham-react";
 import { Badge } from "@gouvfr-lasuite/ui-kit";
 import { useTranslation } from "react-i18next";
 import type { IcsAttendee, IcsOrganizer } from "ts-ics";
+import {
+  useUserSearch,
+  type UserSearchResult,
+} from "@/features/users/hooks/useUserSearch";
+import { filterSuggestions, isValidEmail } from "./attendees-utils";

 interface AttendeesInputProps {
  attendees: IcsAttendee[];
@@ -11,11 +22,6 @@ interface AttendeesInputProps {
  organizer?: IcsOrganizer;
 }

-const isValidEmail = (email: string): boolean => {
-  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
-  return emailRegex.test(email);
-};
-
 type BadgeType =
  | "accent"
  | "neutral"
@@ -59,40 +65,86 @@ export function AttendeesInput({
  const { t } = useTranslation();
  const [inputValue, setInputValue] = useState("");
  const [error, setError] = useState<string | null>(null);
+  const [highlightedIndex, setHighlightedIndex] = useState(-1);
+  const [showSuggestions, setShowSuggestions] = useState(false);
+  const containerRef = useRef<HTMLDivElement>(null);

-  const addAttendee = useCallback(() => {
-    const email = inputValue.trim().toLowerCase();
+  const { data: searchResults, isLoading: isSearching } =
+    useUserSearch(inputValue);

-    if (!email) {
-      return;
-    }
+  // Filter out already-added attendees and the organizer
+  const suggestions = filterSuggestions(
+    searchResults ?? [],
+    attendees,
+    organizerEmail,
+  );

-    if (!isValidEmail(email)) {
-      setError(t("calendar.attendees.invalidEmail"));
-      return;
-    }
+  // Show suggestions when we have results or are searching with enough chars
+  const trimmedInput = inputValue.trim();
+  const shouldShowDropdown =
+    showSuggestions && trimmedInput.length >= 3 && !isSearching;
+  const hasNoResults =
+    shouldShowDropdown &&
+    suggestions.length === 0 &&
+    searchResults !== undefined;

-    if (attendees.some((a) => a.email.toLowerCase() === email)) {
-      setError(t("calendar.attendees.alreadyAdded"));
-      return;
-    }
-
-    if (organizerEmail && email === organizerEmail.toLowerCase()) {
-      setError(t("calendar.attendees.cannotAddOrganizer"));
-      return;
-    }
-
-    const newAttendee: IcsAttendee = {
-      email,
-      partstat: "NEEDS-ACTION",
-      rsvp: true,
-      role: "REQ-PARTICIPANT",
+  // Close dropdown when clicking outside
+  useEffect(() => {
+    const handleClickOutside = (e: MouseEvent) => {
+      if (
+        containerRef.current &&
+        !containerRef.current.contains(e.target as Node)
+      ) {
+        setShowSuggestions(false);
+      }
    };
+    document.addEventListener("mousedown", handleClickOutside);
+    return () => document.removeEventListener("mousedown", handleClickOutside);
+  }, []);

-    onChange([...attendees, newAttendee]);
-    setInputValue("");
-    setError(null);
-  }, [inputValue, attendees, onChange, organizerEmail, t]);
+  const addAttendeeByEmail = useCallback(
+    (email: string, fullName?: string) => {
+      const normalized = email.trim().toLowerCase();
+      if (!normalized) return;
+
+      if (!isValidEmail(normalized)) {
+        setError(t("calendar.attendees.invalidEmail"));
+        return;
+      }
+
+      if (attendees.some((a) => a.email.toLowerCase() === normalized)) {
+        setError(t("calendar.attendees.alreadyAdded"));
+        return;
+      }
+
+      if (organizerEmail && normalized === organizerEmail.toLowerCase()) {
+        setError(t("calendar.attendees.cannotAddOrganizer"));
+        return;
+      }
+
+      const newAttendee: IcsAttendee = {
+        email: normalized,
+        partstat: "NEEDS-ACTION",
+        rsvp: true,
+        role: "REQ-PARTICIPANT",
+        ...(fullName && { cn: fullName }),
+      };
+
+      onChange([...attendees, newAttendee]);
+      setInputValue("");
+      setError(null);
+      setShowSuggestions(false);
+      setHighlightedIndex(-1);
+    },
+    [attendees, onChange, organizerEmail, t],
+  );
+
+  const selectSuggestion = useCallback(
+    (user: UserSearchResult) => {
+      addAttendeeByEmail(user.email, user.full_name);
+    },
+    [addAttendeeByEmail],
+  );

  const removeAttendee = useCallback(
    (emailToRemove: string) => {
@@ -103,16 +155,52 @@ export function AttendeesInput({

  const handleKeyDown = useCallback(
    (e: KeyboardEvent<HTMLInputElement>) => {
+      if (e.key === "Escape") {
+        setShowSuggestions(false);
+        setHighlightedIndex(-1);
+        return;
+      }
+
+      if (
+        shouldShowDropdown &&
+        suggestions.length > 0 &&
+        (e.key === "ArrowDown" || e.key === "ArrowUp")
+      ) {
+        e.preventDefault();
+        setHighlightedIndex((prev) => {
+          if (e.key === "ArrowDown") {
+            return prev < suggestions.length - 1 ? prev + 1 : 0;
+          }
+          return prev > 0 ? prev - 1 : suggestions.length - 1;
+        });
+        return;
+      }
+
      if (e.key === "Enter") {
        e.preventDefault();
-        addAttendee();
+        if (
+          shouldShowDropdown &&
+          highlightedIndex >= 0 &&
+          highlightedIndex < suggestions.length
+        ) {
+          selectSuggestion(suggestions[highlightedIndex]);
+        } else {
+          addAttendeeByEmail(inputValue);
+        }
      }
    },
-    [addAttendee],
+    [
+      shouldShowDropdown,
+      suggestions,
+      highlightedIndex,
+      selectSuggestion,
+      addAttendeeByEmail,
+      inputValue,
+    ],
  );

  return (
-    <div className="attendees-input">
+    <div className="attendees-input" ref={containerRef}>
      <div className="attendees-input__field">
        <Input
          label={t("calendar.attendees.label")}
@@ -123,12 +211,49 @@ export function AttendeesInput({
          value={inputValue}
          onChange={(e) => {
            setInputValue(e.target.value);
+            setShowSuggestions(true);
+            setHighlightedIndex(-1);
            if (error) setError(null);
          }}
          onKeyDown={handleKeyDown}
+          onFocus={() => setShowSuggestions(true)}
          state={error ? "error" : "default"}
          text={error || undefined}
        />
+
+        {(shouldShowDropdown && suggestions.length > 0) || hasNoResults ? (
+          <ul className="attendees-input__suggestions" role="listbox">
+            {suggestions.map((user, index) => (
+              <li
+                key={user.id}
+                role="option"
+                aria-selected={index === highlightedIndex}
+                className={`attendees-input__suggestion${
+                  index === highlightedIndex
+                    ? " attendees-input__suggestion--highlighted"
+                    : ""
+                }`}
+                onMouseDown={(e) => {
+                  e.preventDefault();
+                  selectSuggestion(user);
+                }}
+                onMouseEnter={() => setHighlightedIndex(index)}
+              >
+                <span className="attendees-input__suggestion-name">
+                  {user.full_name}
+                </span>
+                <span className="attendees-input__suggestion-email">
+                  {user.email}
+                </span>
+              </li>
+            ))}
+            {hasNoResults && (
+              <li className="attendees-input__suggestion attendees-input__suggestion--empty">
+                {t("calendar.attendees.noResults")}
+              </li>
+            )}
+          </ul>
+        ) : null}
      </div>

      <div className="attendees-input__pills">
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/EventModal.tsx
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/EventModal.tsx
@@ -21,6 +21,7 @@ import { AttendeesSection } from "./event-modal-sections/AttendeesSection";
 import { ResourcesSection } from "./event-modal-sections/ResourcesSection";
 import { DescriptionSection } from "./event-modal-sections/DescriptionSection";
 import { InvitationResponseSection } from "./event-modal-sections/InvitationResponseSection";
+import { FreeBusySection } from "./event-modal-sections/FreeBusySection";
 import { SectionPills } from "./event-modal-sections/SectionPills";
 import { useResourcePrincipals } from "@/features/resources/api/useResourcePrincipals";
 import type { EventModalProps, RecurringDeleteOption } from "./types";
@@ -176,6 +177,11 @@ export const EventModal = ({
            },
          ]
        : []),
+      {
+        id: "scheduling" as const,
+        icon: "event_available",
+        label: t("scheduling.findATime"),
+      },
    ],
    [t, visioBaseUrl, availableResources.length],
  );
@@ -305,6 +311,25 @@ export const EventModal = ({
              alwaysOpen
            />
          )}
+          {form.isSectionExpanded("scheduling") && (
+            <FreeBusySection
+              attendees={form.attendees}
+              resourceEmails={form.resources
+                .map((r) => r.email)
+                .filter((e): e is string => !!e)}
+              resourceNames={Object.fromEntries(
+                form.resources
+                  .filter((r) => r.email)
+                  .map((r) => [r.email!.toLowerCase(), r.name]),
+              )}
+              organizerEmail={user?.email}
+              startDateTime={form.startDateTime}
+              endDateTime={form.endDateTime}
+              onStartChange={form.setStartDateTime}
+              onEndChange={form.setEndDateTime}
+              alwaysOpen
+            />
+          )}
          {availableResources.length > 0 &&
            form.isSectionExpanded("resources") && (
              <ResourcesSection
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/FreeBusyTimeline.scss
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/FreeBusyTimeline.scss
@@ -0,0 +1,144 @@
+.freebusy-timeline {
+  padding: 0.25rem 0;
+
+  &__header {
+    display: flex;
+    align-items: center;
+    gap: 0.25rem;
+    margin-bottom: 0.25rem;
+  }
+
+  &__nav {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    width: 24px;
+    height: 24px;
+    border: none;
+    border-radius: 50%;
+    background: none;
+    cursor: pointer;
+    color: #5f6368;
+    padding: 0;
+
+    &:hover {
+      background-color: #f1f3f4;
+    }
+
+    .material-icons {
+      font-size: 18px;
+    }
+  }
+
+  &__date {
+    font-size: 0.75rem;
+    font-weight: 500;
+    color: #202124;
+    min-width: 100px;
+    text-align: center;
+  }
+
+  &__loading {
+    display: flex;
+    align-items: center;
+    margin-left: auto;
+  }
+
+  &__spinner {
+    font-size: 14px;
+    color: #5f6368;
+    animation: freebusy-spin 1.5s linear infinite;
+  }
+
+  &__status {
+    font-size: 0.6875rem;
+    margin-left: auto;
+    padding: 0.0625rem 0.375rem;
+    border-radius: 8px;
+
+    &--ok {
+      color: #137333;
+      background-color: #e6f4ea;
+    }
+
+    &--conflict {
+      color: #c5221f;
+      background-color: #fce8e6;
+    }
+  }
+
+  &__calendar {
+    border: 1px solid #e0e0e0;
+    border-radius: 4px;
+    overflow: hidden;
+
+    // Hide the day name row (e.g. "Monday") — redundant with our nav header
+    .ec-col-head {
+      display: none;
+    }
+
+    // Shrink the resource label column
+    .ec-sidebar {
+      width: 90px !important;
+      min-width: 90px !important;
+      max-width: 90px !important;
+      flex-shrink: 0;
+    }
+
+    .ec-resource {
+      font-size: 0.625rem;
+      padding: 0 2px;
+      white-space: nowrap;
+      overflow: hidden;
+      text-overflow: ellipsis;
+    }
+
+    // Compact row heights, no row separators
+    .ec-body .ec-resource {
+      height: 24px !important;
+      border-bottom: none !important;
+    }
+
+    // Smaller time header labels
+    .ec-header .ec-time {
+      font-size: 0.5625rem;
+      padding: 2px 0;
+    }
+
+    .ec-header {
+      height: auto !important;
+      min-height: unset !important;
+    }
+
+    // Single overlay for proposed meeting time across all rows
+    .freebusy-proposed-overlay {
+      border-left: 2px solid #137333;
+      border-right: 2px solid #137333;
+      background: repeating-linear-gradient(
+        -45deg,
+        rgba(19, 115, 51, 0.35),
+        rgba(19, 115, 51, 0.35) 1px,
+        transparent 1px,
+        transparent 7px
+      );
+    }
+  }
+
+  &__empty {
+    padding: 0.75rem;
+    text-align: center;
+    font-size: 0.75rem;
+    color: #5f6368;
+    border: 1px solid #e0e0e0;
+    border-radius: 4px;
+  }
+}
+
+@keyframes freebusy-spin {
+  from {
+    transform: rotate(0deg);
+  }
+  to {
+    transform: rotate(360deg);
+  }
+}
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/FreeBusyTimeline.tsx
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/FreeBusyTimeline.tsx
@@ -0,0 +1,274 @@
+import { useEffect, useRef, useMemo, useCallback } from "react";
+import { useTranslation } from "react-i18next";
+import { createCalendar, destroyCalendar, ResourceTimeline } from "@event-calendar/core";
+import type { FreeBusyResponse } from "../../services/dav/types/caldav-service";
+
+interface FreeBusyTimelineProps {
+  date: Date;
+  attendees: FreeBusyResponse[];
+  displayNames?: Record<string, string>;
+  eventStart: Date;
+  eventEnd: Date;
+  isLoading: boolean;
+  onDateChange: (date: Date) => void;
+  onTimeSelect: (start: Date, end: Date) => void;
+}
+
+/** Map freebusy type to a background color. */
+const BUSY_COLORS: Record<string, string> = {
+  BUSY: "rgba(26, 115, 232, 0.4)",
+  "BUSY-UNAVAILABLE": "rgba(95, 99, 104, 0.5)",
+  "BUSY-TENTATIVE": "rgba(26, 115, 232, 0.2)",
+};
+
+export const FreeBusyTimeline = ({
+  date,
+  attendees,
+  displayNames,
+  eventStart,
+  eventEnd,
+  isLoading,
+  onDateChange,
+  onTimeSelect,
+}: FreeBusyTimelineProps) => {
+  const { t } = useTranslation();
+  const containerRef = useRef<HTMLDivElement>(null);
+  const calendarRef = useRef<ReturnType<typeof createCalendar> | null>(null);
+  const handlersRef = useRef({ onTimeSelect, onDateChange });
+
+  useEffect(() => {
+    handlersRef.current = { onTimeSelect, onDateChange };
+  });
+
+  const eventDurationMs = eventEnd.getTime() - eventStart.getTime();
+  const eventDurationRef = useRef(eventDurationMs);
+  useEffect(() => {
+    eventDurationRef.current = eventDurationMs;
+  }, [eventDurationMs]);
+
+  const dateStr = date.toLocaleDateString(undefined, {
+    weekday: "short",
+    month: "short",
+    day: "numeric",
+  });
+
+  // Map attendees → resources, using displayNames for friendly labels
+  const resources = useMemo(
+    () =>
+      attendees.map((a) => ({
+        id: a.attendee,
+        title:
+          displayNames?.[a.attendee] ??
+          displayNames?.[a.attendee.toLowerCase()] ??
+          a.attendee.split("@")[0],
+      })),
+    [attendees, displayNames],
+  );
+
+  // Map busy periods → background events + proposed event overlay
+  const events = useMemo(() => {
+    const allEvents: {
+      id: string;
+      resourceIds: string[];
+      start: Date;
+      end: Date;
+      display?: string;
+      backgroundColor?: string;
+      title?: string;
+    }[] = attendees.flatMap((a) =>
+      a.periods.map((period, idx) => ({
+        id: `busy-${a.attendee}-${idx}`,
+        resourceIds: [a.attendee],
+        start: period.start,
+        end: period.end,
+        display: "background",
+        backgroundColor: BUSY_COLORS[period.type] ?? BUSY_COLORS.BUSY,
+      })),
+    );
+
+    return allEvents;
+  }, [attendees, date, resources]);
+
+  // Count conflicts
+  const eventOnThisDay =
+    eventStart.toDateString() === date.toDateString() ||
+    eventEnd.toDateString() === date.toDateString() ||
+    (eventStart < date && eventEnd > date);
+  const conflictCount = eventOnThisDay
+    ? attendees.filter((a) =>
+        a.periods.some((p) => p.start < eventEnd && p.end > eventStart),
+      ).length
+    : 0;
+
+  // Create / destroy calendar instance
+  useEffect(() => {
+    if (!containerRef.current) return;
+
+    const ec = createCalendar(containerRef.current, [ResourceTimeline], {
+      view: "resourceTimelineDay",
+      headerToolbar: false,
+      slotMinTime: "07:00",
+      slotMaxTime: "24:00",
+      slotDuration: "01:00",
+      height: "auto",
+      date,
+      resources,
+      events,
+      editable: false,
+      selectable: false,
+      dateClick: (info: { date: Date; resource?: { id: string } }) => {
+        const clickedDate = info.date;
+        const dur = eventDurationRef.current;
+        const newEnd = new Date(clickedDate.getTime() + dur);
+        handlersRef.current.onTimeSelect(clickedDate, newEnd);
+      },
+    });
+
+    calendarRef.current = ec;
+
+    // Make the time grid areas scrollable while keeping sidebar fixed
+    const GRID_WIDTH = 1100;
+    requestAnimationFrame(() => {
+      if (!containerRef.current) return;
+      // Structure: .ec-main > .ec-header, .ec-main > .ec-body
+      const header = containerRef.current.querySelector(
+        ".ec-header",
+      ) as HTMLElement | null;
+      const body = containerRef.current.querySelector(
+        ".ec-body",
+      ) as HTMLElement | null;
+      if (!header || !body) return;
+
+      // The grid inside header/body holds the time slots
+      const headerGrid = header.querySelector(".ec-grid") as HTMLElement | null;
+      const bodyGrid = body.querySelector(".ec-grid") as HTMLElement | null;
+      if (!headerGrid || !bodyGrid) return;
+
+      headerGrid.style.minWidth = `${GRID_WIDTH}px`;
+      bodyGrid.style.minWidth = `${GRID_WIDTH}px`;
+
+      // Make the body scrollable, hide header scrollbar
+      body.style.overflowX = "auto";
+      header.style.overflowX = "hidden";
+
+      // Sync header scroll when body scrolls
+      const onBodyScroll = () => {
+        header.scrollLeft = body.scrollLeft;
+      };
+      body.addEventListener("scroll", onBodyScroll);
+
+      // Scroll to ~8 AM (1 hour into the 7:00-24:00 range)
+      const scrollPos = (1 / 17) * GRID_WIDTH;
+      body.scrollLeft = scrollPos;
+      header.scrollLeft = scrollPos;
+
+      // Inject a single proposed-time overlay spanning all rows
+      const startsOnDay = eventStart.toDateString() === date.toDateString();
+      const endsOnDay = eventEnd.toDateString() === date.toDateString();
+      const spansDay = eventStart < date && eventEnd > date;
+      if ((startsOnDay || endsOnDay || spansDay) && resources.length > 0) {
+        const SLOT_MIN = 7; // slotMinTime hours
+        const SLOT_MAX = 24; // slotMaxTime hours
+        const totalHours = SLOT_MAX - SLOT_MIN;
+        const startH = startsOnDay
+          ? eventStart.getHours() + eventStart.getMinutes() / 60
+          : SLOT_MIN;
+        const endH = endsOnDay
+          ? eventEnd.getHours() + eventEnd.getMinutes() / 60
+          : SLOT_MAX;
+        const leftPct = ((Math.max(startH, SLOT_MIN) - SLOT_MIN) / totalHours) * 100;
+        const rightPct = ((Math.min(endH, SLOT_MAX) - SLOT_MIN) / totalHours) * 100;
+
+        if (rightPct > leftPct) {
+          const overlay = document.createElement("div");
+          overlay.className = "freebusy-proposed-overlay";
+          overlay.style.position = "absolute";
+          overlay.style.top = "0";
+          overlay.style.bottom = "0";
+          overlay.style.left = `${leftPct}%`;
+          overlay.style.width = `${rightPct - leftPct}%`;
+          overlay.style.pointerEvents = "none";
+          overlay.style.zIndex = "5";
+
+          bodyGrid.style.position = "relative";
+          bodyGrid.appendChild(overlay);
+        }
+      }
+    });
+
+    return () => {
+      if (calendarRef.current) {
+        destroyCalendar(calendarRef.current);
+        calendarRef.current = null;
+      }
+      if (containerRef.current) {
+        containerRef.current.innerHTML = "";
+      }
+    };
+    // Recreate when data changes
+  }, [date, resources, events, eventStart, eventEnd]);
+
+  const handlePrev = useCallback(() => {
+    const prev = new Date(date);
+    prev.setDate(prev.getDate() - 1);
+    onDateChange(prev);
+  }, [date, onDateChange]);
+
+  const handleNext = useCallback(() => {
+    const next = new Date(date);
+    next.setDate(next.getDate() + 1);
+    onDateChange(next);
+  }, [date, onDateChange]);
+
+  return (
+    <div className="freebusy-timeline">
+      <div className="freebusy-timeline__header">
+        <button
+          type="button"
+          className="freebusy-timeline__nav"
+          onClick={handlePrev}
+          aria-label={t("scheduling.previousDay")}
+        >
+          <span className="material-icons">chevron_left</span>
+        </button>
+        <span className="freebusy-timeline__date">{dateStr}</span>
+        <button
+          type="button"
+          className="freebusy-timeline__nav"
+          onClick={handleNext}
+          aria-label={t("scheduling.nextDay")}
+        >
+          <span className="material-icons">chevron_right</span>
+        </button>
+        {isLoading && (
+          <span className="freebusy-timeline__loading">
+            <span className="material-icons freebusy-timeline__spinner">
+              sync
+            </span>
+          </span>
+        )}
+        {!isLoading && eventOnThisDay && (
+          <span
+            className={`freebusy-timeline__status ${
+              conflictCount > 0
+                ? "freebusy-timeline__status--conflict"
+                : "freebusy-timeline__status--ok"
+            }`}
+          >
+            {conflictCount > 0
+              ? t("scheduling.conflicts", { count: conflictCount })
+              : t("scheduling.noConflicts")}
+          </span>
+        )}
+      </div>
+
+      {attendees.length === 0 && !isLoading ? (
+        <div className="freebusy-timeline__empty">
+          {t("scheduling.addAttendeesToSeeAvailability")}
+        </div>
+      ) : (
+        <div ref={containerRef} className="freebusy-timeline__calendar" />
+      )}
+    </div>
+  );
+};
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/tests/attendees-utils.test.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/tests/attendees-utils.test.ts
@@ -0,0 +1,123 @@
+import { filterSuggestions, isValidEmail } from "../attendees-utils";
+import type { UserSearchResult } from "@/features/users/hooks/useUserSearch";
+import type { IcsAttendee } from "ts-ics";
+
+describe("attendees-utils", () => {
+  describe("isValidEmail", () => {
+    it("accepts a valid email", () => {
+      expect(isValidEmail("user@example.com")).toBe(true);
+    });
+
+    it("rejects an empty string", () => {
+      expect(isValidEmail("")).toBe(false);
+    });
+
+    it("rejects a string without @", () => {
+      expect(isValidEmail("not-an-email")).toBe(false);
+    });
+
+    it("rejects a string without domain", () => {
+      expect(isValidEmail("user@")).toBe(false);
+    });
+
+    it("rejects a string with spaces", () => {
+      expect(isValidEmail("user @example.com")).toBe(false);
+    });
+  });
+
+  describe("filterSuggestions", () => {
+    const makeUser = (
+      email: string,
+      name = "Test User",
+    ): UserSearchResult => ({
+      id: email,
+      email,
+      full_name: name,
+    });
+
+    const makeAttendee = (email: string): IcsAttendee => ({
+      email,
+      partstat: "NEEDS-ACTION",
+      rsvp: true,
+      role: "REQ-PARTICIPANT",
+    });
+
+    it("returns all suggestions when no attendees or organizer", () => {
+      const results = [
+        makeUser("alice@org.com", "Alice"),
+        makeUser("bob@org.com", "Bob"),
+      ];
+      expect(filterSuggestions(results, [])).toEqual(results);
+    });
+
+    it("filters out already-added attendees", () => {
+      const results = [
+        makeUser("alice@org.com"),
+        makeUser("bob@org.com"),
+        makeUser("carol@org.com"),
+      ];
+      const attendees = [makeAttendee("alice@org.com")];
+      const filtered = filterSuggestions(results, attendees);
+      expect(filtered).toHaveLength(2);
+      expect(filtered.map((u) => u.email)).toEqual([
+        "bob@org.com",
+        "carol@org.com",
+      ]);
+    });
+
+    it("filters case-insensitively", () => {
+      const results = [makeUser("Alice@Org.com")];
+      const attendees = [makeAttendee("alice@org.com")];
+      expect(filterSuggestions(results, attendees)).toHaveLength(0);
+    });
+
+    it("filters out the organizer email", () => {
+      const results = [
+        makeUser("organizer@org.com"),
+        makeUser("other@org.com"),
+      ];
+      const filtered = filterSuggestions(
+        results,
+        [],
+        "organizer@org.com",
+      );
+      expect(filtered).toHaveLength(1);
+      expect(filtered[0].email).toBe("other@org.com");
+    });
+
+    it("filters organizer case-insensitively", () => {
+      const results = [makeUser("Organizer@Org.COM")];
+      const filtered = filterSuggestions(
+        results,
+        [],
+        "organizer@org.com",
+      );
+      expect(filtered).toHaveLength(0);
+    });
+
+    it("filters both attendees and organizer together", () => {
+      const results = [
+        makeUser("organizer@org.com"),
+        makeUser("attendee@org.com"),
+        makeUser("available@org.com"),
+      ];
+      const attendees = [makeAttendee("attendee@org.com")];
+      const filtered = filterSuggestions(
+        results,
+        attendees,
+        "organizer@org.com",
+      );
+      expect(filtered).toHaveLength(1);
+      expect(filtered[0].email).toBe("available@org.com");
+    });
+
+    it("filters out users with no email", () => {
+      const results = [{ id: "1", email: "", full_name: "No Email" }];
+      expect(filterSuggestions(results, [])).toHaveLength(0);
+    });
+
+    it("returns empty array for empty results", () => {
+      expect(filterSuggestions([], [])).toEqual([]);
+    });
+  });
+});
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/attendees-utils.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/attendees-utils.ts
@@ -0,0 +1,25 @@
+import type { IcsAttendee } from "ts-ics";
+import type { UserSearchResult } from "@/features/users/hooks/useUserSearch";
+
+/**
+ * Filter search results to exclude already-added attendees
+ * and the organizer email.
+ */
+export function filterSuggestions(
+  searchResults: UserSearchResult[],
+  attendees: IcsAttendee[],
+  organizerEmail?: string,
+): UserSearchResult[] {
+  return searchResults.filter((user) => {
+    const email = user.email?.toLowerCase();
+    if (!email) return false;
+    if (attendees.some((a) => a.email.toLowerCase() === email)) return false;
+    if (organizerEmail && email === organizerEmail.toLowerCase()) return false;
+    return true;
+  });
+}
+
+export const isValidEmail = (email: string): boolean => {
+  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+  return emailRegex.test(email);
+};
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/event-modal-sections/FreeBusySection.tsx
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/event-modal-sections/FreeBusySection.tsx
@@ -0,0 +1,97 @@
+import { useMemo } from "react";
+import { useTranslation } from "react-i18next";
+import type { IcsAttendee } from "ts-ics";
+import { useCalendarContext } from "../../../contexts/CalendarContext";
+import { useFreeBusy } from "../hooks/useFreeBusy";
+import { FreeBusyTimeline } from "../FreeBusyTimeline";
+import { SectionRow } from "./SectionRow";
+import {
+  formatDateTimeLocal,
+  parseDateTimeLocal,
+} from "../utils/dateFormatters";
+
+interface FreeBusySectionProps {
+  attendees: IcsAttendee[];
+  resourceEmails?: string[];
+  resourceNames?: Record<string, string>;
+  organizerEmail?: string;
+  startDateTime: string;
+  endDateTime: string;
+  onStartChange: (value: string) => void;
+  onEndChange: (value: string) => void;
+  alwaysOpen?: boolean;
+}
+
+export const FreeBusySection = ({
+  attendees,
+  resourceEmails,
+  resourceNames,
+  organizerEmail,
+  startDateTime,
+  endDateTime,
+  onStartChange,
+  onEndChange,
+  alwaysOpen,
+}: FreeBusySectionProps) => {
+  const { t } = useTranslation();
+  const { caldavService } = useCalendarContext();
+
+  const eventStart = useMemo(
+    () => parseDateTimeLocal(startDateTime),
+    [startDateTime],
+  );
+  const eventEnd = useMemo(
+    () => parseDateTimeLocal(endDateTime),
+    [endDateTime],
+  );
+
+  const allEmails = useMemo(
+    () => [
+      ...attendees.map((a) => a.email.toLowerCase()),
+      ...(resourceEmails ?? []).map((e) => e.toLowerCase()),
+    ],
+    [attendees, resourceEmails],
+  );
+
+  const { data, isLoading } = useFreeBusy({
+    caldavService,
+    attendees: allEmails,
+    organizerEmail,
+    date: eventStart,
+    enabled: allEmails.length > 0,
+  });
+
+  const handleDateChange = (date: Date) => {
+    const newStart = new Date(eventStart);
+    newStart.setFullYear(date.getFullYear(), date.getMonth(), date.getDate());
+    const newEnd = new Date(eventEnd);
+    newEnd.setFullYear(date.getFullYear(), date.getMonth(), date.getDate());
+    onStartChange(formatDateTimeLocal(newStart));
+    onEndChange(formatDateTimeLocal(newEnd));
+  };
+
+  const handleTimeSelect = (start: Date, end: Date) => {
+    onStartChange(formatDateTimeLocal(start));
+    onEndChange(formatDateTimeLocal(end));
+  };
+
+  return (
+    <SectionRow
+      icon="event_available"
+      label={t("scheduling.findATime")}
+      alwaysOpen={alwaysOpen}
+      iconAlign="flex-start"
+    >
+      <FreeBusyTimeline
+        date={eventStart}
+        attendees={data}
+        displayNames={resourceNames}
+        eventStart={eventStart}
+        eventEnd={eventEnd}
+        isLoading={isLoading}
+        onDateChange={handleDateChange}
+        onTimeSelect={handleTimeSelect}
+      />
+    </SectionRow>
+  );
+};
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useEventForm.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useEventForm.ts
@@ -426,6 +426,7 @@ export const useEventForm = ({
    location,
    setLocation,
    startDateTime,
+    setStartDateTime,
    endDateTime,
    setEndDateTime,
    selectedCalendarUrl,
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useFreeBusy.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useFreeBusy.ts
@@ -0,0 +1,78 @@
+import { useQuery, useQueryClient } from "@tanstack/react-query";
+import { useCallback, useMemo } from "react";
+import type { FreeBusyResponse } from "../../../services/dav/types/caldav-service";
+import type { CalDavService } from "../../../services/dav/CalDavService";
+
+interface UseFreeBusyOptions {
+  caldavService: CalDavService;
+  attendees: string[];
+  organizerEmail?: string;
+  date: Date;
+  enabled: boolean;
+}
+
+interface UseFreeBusyResult {
+  data: FreeBusyResponse[];
+  isLoading: boolean;
+  error: string | null;
+  refresh: () => void;
+}
+
+/**
+ * Hook to query freebusy data for a list of attendees on a given date.
+ * Automatically re-queries when attendees or date change.
+ */
+export function useFreeBusy({
+  caldavService,
+  attendees,
+  organizerEmail,
+  date,
+  enabled,
+}: UseFreeBusyOptions): UseFreeBusyResult {
+  const queryClient = useQueryClient();
+
+  // Stable key: sort attendees so order doesn't trigger refetch
+  const attendeesKey = useMemo(
+    () => [...attendees].sort().join(","),
+    [attendees],
+  );
+  const dateKey = date.toISOString().slice(0, 10);
+
+  const queryKey = ["freebusy", attendeesKey, organizerEmail, dateKey];
+
+  const query = useQuery({
+    queryKey,
+    queryFn: async (): Promise<FreeBusyResponse[]> => {
+      const start = new Date(date);
+      start.setHours(0, 0, 0, 0);
+      const end = new Date(date);
+      end.setHours(23, 59, 59, 999);
+
+      const result = await caldavService.queryFreeBusy({
+        attendees,
+        timeRange: { start, end },
+        organizer: organizerEmail
+          ? { email: organizerEmail, name: organizerEmail.split("@")[0] }
+          : undefined,
+      });
+
+      if (result.success && result.data) {
+        return result.data;
+      }
+      throw new Error(result.error ?? "Failed to query availability");
+    },
+    enabled: enabled && attendees.length > 0,
+    retry: false,
+  });
+
+  const refresh = useCallback(() => {
+    void queryClient.invalidateQueries({ queryKey });
+  }, [queryClient, queryKey]);
+
+  return {
+    data: query.data ?? [],
+    isLoading: query.isLoading,
+    error: query.error?.message ?? null,
+    refresh,
+  };
+}
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useSchedulerInit.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useSchedulerInit.ts
@@ -7,6 +7,7 @@ import { useEffect, useRef, MutableRefObject } from "react";
 import { useTranslation } from "react-i18next";
 import {
  createCalendar,
+  destroyCalendar,
  TimeGrid,
  DayGrid,
  List,
@@ -252,13 +253,9 @@ export const useSchedulerInit = ({
    calendarRef.current = ec as unknown as CalendarApi;

    return () => {
-      // @event-calendar/core is Svelte-based and uses $destroy
-      // Always call $destroy before clearing the container to avoid memory leaks
      if (calendarRef.current) {
-        const calendar = calendarRef.current as CalendarApi;
-        if (typeof calendar.$destroy === 'function') {
-          calendar.$destroy();
-        }
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        destroyCalendar(calendarRef.current as any);
        calendarRef.current = null;
      }
      // Clear the container only after calendar is destroyed
--- a/src/frontend/apps/calendars/src/features/calendar/components/scheduler/types.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/components/scheduler/types.ts
@@ -83,7 +83,8 @@ export type EventFormSectionId =
  | "recurrence"
  | "attendees"
  | "resources"
-  | "videoConference";
+  | "videoConference"
+  | "scheduling";

 /**
 * Attachment metadata (UI only, no actual file upload).
@@ -130,7 +131,6 @@ export interface CalendarApi {
  addEvent: (event: unknown) => void;
  unselect: () => void;
  refetchEvents: () => void;
-  $destroy?: () => void;
 }

 /**
--- a/src/frontend/apps/calendars/src/features/calendar/services/dav/CalDavService.ts
+++ b/src/frontend/apps/calendars/src/features/calendar/services/dav/CalDavService.ts
@@ -62,6 +62,7 @@ import {
  buildSyncCollectionXml,
  buildPrincipalSearchXml,
  executeDavRequest,
+  escapeXml,
  CALENDAR_PROPS,
  parseCalendarComponents,
  parseSharePrivilege,
@@ -793,20 +794,22 @@ export class CalDavService {
        throw new Error('Scheduling outbox not found')
      }

-      // Construct full URL - outboxUrl is relative to serverUrl
+      // Construct full URL - outboxUrl from PROPFIND is an absolute path (e.g. /caldav/calendars/...)
+      // so we only need to prepend the origin, not the full serverUrl (which already has /caldav/)
      const fullOutboxUrl = outboxUrl.startsWith('http')
        ? outboxUrl
-        : `${this._account!.serverUrl}${outboxUrl.startsWith('/') ? outboxUrl.slice(1) : outboxUrl}`
+        : `${new URL(this._account!.serverUrl).origin}${outboxUrl}`

      // Use fetch directly to avoid davRequest URL construction issues in dev mode
+      // Note: fetchOptions is spread first so its headers don't override our Content-Type
      const response = await fetch(fullOutboxUrl, {
+        ...this._account!.fetchOptions,
        method: 'POST',
        headers: {
-          'Content-Type': 'text/calendar; charset=utf-8; method=' + request.method,
          ...this._account!.headers,
+          'Content-Type': 'text/calendar; charset=utf-8; method=' + request.method,
        },
        body: iCalString,
-        ...this._account!.fetchOptions,
      })

      if (!response.ok) {
@@ -910,31 +913,91 @@ ${attendeeLines}
 END:VFREEBUSY
 END:VCALENDAR`

-      const responses = await davRequest({
-        url: outboxUrl,
-        init: {
-          method: 'POST',
-          headers: {
-            'Content-Type': 'text/calendar; charset=utf-8',
-            ...this._account!.headers,
-          },
-          body: fbRequest,
+      // Construct full URL - outboxUrl from PROPFIND is an absolute path (e.g. /caldav/calendars/...)
+      // so we only need to prepend the origin, not the full serverUrl (which already has /caldav/)
+      const fullOutboxUrl = outboxUrl.startsWith('http')
+        ? outboxUrl
+        : `${new URL(this._account!.serverUrl).origin}${outboxUrl}`
+
+      // Note: fetchOptions is spread first so its headers don't override our Content-Type
+      const response = await fetch(fullOutboxUrl, {
+        ...this._account!.fetchOptions,
+        method: 'POST',
+        headers: {
+          ...this._account!.headers,
+          'Content-Type': 'text/calendar; charset=utf-8',
        },
-        fetchOptions: this._account!.fetchOptions,
+        body: fbRequest,
      })

-      const response = responses[0]
-      if (!response?.ok) {
-        throw new Error(`Failed to query free/busy: ${response?.status}`)
+      if (!response.ok) {
+        throw new Error(`Failed to query free/busy: ${response.status}`)
      }

-      return request.attendees.map((email) => ({
-        attendee: email,
-        periods: [],
-      }))
+      const xmlText = await response.text()
+      return parseScheduleFreeBusyResponse(xmlText)
    }, 'Failed to query free/busy')
  }

+  // ============================================================================
+  // Availability (Working Hours)
+  // ============================================================================
+
+  /**
+   * Get the user's calendar availability (working hours).
+   * Reads the {urn:ietf:params:xml:ns:caldav}calendar-availability property
+   * from the calendar home via PROPFIND.
+   */
+  async getAvailability(): Promise<CalDavResponse<string | null>> {
+    if (!this._account?.homeUrl) {
+      return { success: false, error: 'Not connected' }
+    }
+
+    return withErrorHandling(async () => {
+      const response = await propfind({
+        url: this._account!.homeUrl!,
+        props: {
+          [`${DAVNamespaceShort.CALDAV}:calendar-availability`]: {},
+        },
+        headers: this._account!.headers,
+        fetchOptions: this._account!.fetchOptions,
+        depth: '0',
+      })
+
+      return response[0]?.props?.['calendarAvailability'] ?? null
+    }, 'Failed to get availability')
+  }
+
+  /**
+   * Set the user's calendar availability (working hours).
+   * Stores a VCALENDAR with VAVAILABILITY/AVAILABLE components
+   * on the calendar home via PROPPATCH.
+   */
+  async setAvailability(
+    vcalendarText: string,
+  ): Promise<CalDavResponse> {
+    if (!this._account?.homeUrl) {
+      return { success: false, error: 'Not connected' }
+    }
+
+    const body = `<?xml version="1.0" encoding="utf-8"?>
+<D:propertyupdate xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+  <D:set>
+    <D:prop>
+      <C:calendar-availability>${escapeXml(vcalendarText)}</C:calendar-availability>
+    </D:prop>
+  </D:set>
+</D:propertyupdate>`
+
+    return executeDavRequest({
+      url: this._account.homeUrl,
+      method: 'PROPPATCH',
+      body,
+      headers: this._account.headers,
+      fetchOptions: this._account.fetchOptions,
+    })
+  }
+
  // ============================================================================
  // Sync Operations
  // ============================================================================
@@ -1189,3 +1252,127 @@ END:VCALENDAR`
 export function createCalDavService(): CalDavService {
  return new CalDavService()
 }
+
+// ============================================================================
+// FreeBusy Response Parsing
+// ============================================================================
+
+/**
+ * Parse a CalDAV schedule-response XML containing VFREEBUSY data.
+ * Response format defined in RFC 6638.
+ */
+function parseScheduleFreeBusyResponse(
+  xmlText: string,
+): FreeBusyResponse[] {
+  const parser = new DOMParser()
+  const doc = parser.parseFromString(xmlText, 'application/xml')
+
+  const results: FreeBusyResponse[] = []
+  const CAL_NS = 'urn:ietf:params:xml:ns:caldav'
+  const DAV_NS = 'DAV:'
+
+  const responseElements = doc.getElementsByTagNameNS(CAL_NS, 'response')
+
+  for (let i = 0; i < responseElements.length; i++) {
+    const responseEl = responseElements[i]
+
+    // Check request-status — skip unknown users (3.x = error)
+    const statusEl = responseEl.getElementsByTagNameNS(CAL_NS, 'request-status')[0]
+    const status = statusEl?.textContent ?? ''
+    if (status.startsWith('3.')) continue
+
+    // Extract recipient email
+    const recipientEl = responseEl.getElementsByTagNameNS(CAL_NS, 'recipient')[0]
+    const hrefEl = recipientEl?.getElementsByTagNameNS(DAV_NS, 'href')[0]
+    const href = hrefEl?.textContent ?? ''
+    const email = href.replace(/^mailto:/i, '').toLowerCase()
+
+    // Extract calendar-data (ICS text containing VFREEBUSY)
+    const calDataEl = responseEl.getElementsByTagNameNS(CAL_NS, 'calendar-data')[0]
+    const icsText = calDataEl?.textContent ?? ''
+
+    const periods = parseFreeBusyPeriods(icsText)
+    results.push({ attendee: email, periods })
+  }
+
+  return results
+}
+
+/**
+ * Parse FREEBUSY lines from a VFREEBUSY ICS component.
+ * Format: FREEBUSY;FBTYPE=BUSY:20260310T090000Z/20260310T100000Z
+ */
+function parseFreeBusyPeriods(icsText: string): FreeBusyResponse['periods'] {
+  const periods: FreeBusyResponse['periods'] = []
+  const lines = icsText.split(/\r?\n/)
+
+  for (const line of lines) {
+    if (!line.startsWith('FREEBUSY')) continue
+
+    // Split into params and value: FREEBUSY;FBTYPE=BUSY:start/end
+    const colonIdx = line.indexOf(':')
+    if (colonIdx === -1) continue
+
+    const params = line.substring(0, colonIdx)
+    const value = line.substring(colonIdx + 1)
+
+    // Parse FBTYPE (default BUSY)
+    let fbType: 'BUSY' | 'BUSY-UNAVAILABLE' | 'BUSY-TENTATIVE' | 'FREE' = 'BUSY'
+    const typeMatch = params.match(/FBTYPE=([A-Z-]+)/i)
+    if (typeMatch) {
+      fbType = typeMatch[1].toUpperCase() as typeof fbType
+    }
+
+    // Parse comma-separated periods
+    const periodStrs = value.split(',')
+    for (const periodStr of periodStrs) {
+      const [startStr, endStr] = periodStr.split('/')
+      if (!startStr || !endStr) continue
+
+      const start = parseIcsDateTime(startStr)
+      if (!start) continue
+
+      let end: Date | null
+      if (endStr.startsWith('P')) {
+        // Duration format (e.g., PT1H)
+        end = addIsoDuration(start, endStr)
+      } else {
+        end = parseIcsDateTime(endStr)
+      }
+      if (!end) continue
+
+      periods.push({ start, end, type: fbType })
+    }
+  }
+
+  return periods
+}
+
+/** Parse an ICS datetime string like 20260310T090000Z into a Date. */
+function parseIcsDateTime(str: string): Date | null {
+  const m = str.match(/^(\d{4})(\d{2})(\d{2})T(\d{2})(\d{2})(\d{2})Z?$/)
+  if (!m) return null
+  return new Date(
+    Date.UTC(
+      parseInt(m[1]),
+      parseInt(m[2]) - 1,
+      parseInt(m[3]),
+      parseInt(m[4]),
+      parseInt(m[5]),
+      parseInt(m[6]),
+    ),
+  )
+}
+
+/** Add an ISO 8601 duration (e.g., PT1H30M) to a Date. */
+function addIsoDuration(date: Date, duration: string): Date {
+  const m = duration.match(/P(?:(\d+)D)?T?(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?/)
+  if (!m) return date
+  const ms =
+    (parseInt(m[1] || '0') * 86400 +
+      parseInt(m[2] || '0') * 3600 +
+      parseInt(m[3] || '0') * 60 +
+      parseInt(m[4] || '0')) *
+    1000
+  return new Date(date.getTime() + ms)
+}
--- a/src/frontend/apps/calendars/src/features/i18n/translations.json
+++ b/src/frontend/apps/calendars/src/features/i18n/translations.json
@@ -28,7 +28,28 @@
      "logout": "Logout",
      "login": "Login",
      "my_account": "My Account",
-      "settings": "Settings",
+      "settings": {
+        "label": "Settings",
+        "workingHours": {
+          "title": "Working Hours",
+          "description": "Set your available hours for scheduling",
+          "when": "When",
+          "everyMonday": "Every Monday",
+          "everyTuesday": "Every Tuesday",
+          "everyWednesday": "Every Wednesday",
+          "everyThursday": "Every Thursday",
+          "everyFriday": "Every Friday",
+          "everySaturday": "Every Saturday",
+          "everySunday": "Every Sunday",
+          "specificDate": "Specific date...",
+          "start": "Start",
+          "end": "End",
+          "addAvailability": "Add availability",
+          "removeAvailability": "Remove",
+          "save": "Save",
+          "saved": "Working hours saved"
+        }
+      },
      "api": {
        "error": {
          "unexpected": "An unexpected error occurred."
@@ -331,7 +352,8 @@
          "participants": "Participants",
          "organizer": "Organizer",
          "viewProfile": "View profile",
-          "cannotRemoveOrganizer": "Cannot remove organizer"
+          "cannotRemoveOrganizer": "Cannot remove organizer",
+          "noResults": "No users found"
        },
        "resources": {
          "placeholder": "Select a resource...",
@@ -514,6 +536,14 @@
          "copy": "Copy token",
          "copied": "Token copied to clipboard."
        }
+      },
+      "scheduling": {
+        "findATime": "Find a time",
+        "previousDay": "Previous day",
+        "nextDay": "Next day",
+        "noConflicts": "No conflicts",
+        "conflicts": "{{count}} conflict(s)",
+        "addAttendeesToSeeAvailability": "Add attendees to see availability"
      }
    }
  },
@@ -585,7 +615,28 @@
      "logout": "Déconnexion",
      "login": "Connexion",
      "my_account": "Mon Compte",
-      "settings": "Paramètres",
+      "settings": {
+        "label": "Paramètres",
+        "workingHours": {
+          "title": "Heures de travail",
+          "description": "Définissez vos heures de disponibilité pour la planification",
+          "when": "Quand",
+          "everyMonday": "Chaque lundi",
+          "everyTuesday": "Chaque mardi",
+          "everyWednesday": "Chaque mercredi",
+          "everyThursday": "Chaque jeudi",
+          "everyFriday": "Chaque vendredi",
+          "everySaturday": "Chaque samedi",
+          "everySunday": "Chaque dimanche",
+          "specificDate": "Date spécifique...",
+          "start": "Début",
+          "end": "Fin",
+          "addAvailability": "Ajouter une disponibilité",
+          "removeAvailability": "Supprimer",
+          "save": "Enregistrer",
+          "saved": "Heures de travail enregistrées"
+        }
+      },
      "api": {
        "error": {
          "unexpected": "Une erreur inattendue est survenue."
@@ -1152,7 +1203,8 @@
          "participants": "Participants",
          "organizer": "Organisateur",
          "viewProfile": "Voir le profil",
-          "cannotRemoveOrganizer": "Impossible de retirer l'organisateur"
+          "cannotRemoveOrganizer": "Impossible de retirer l'organisateur",
+          "noResults": "Aucun utilisateur trouvé"
        },
        "resources": {
          "placeholder": "Sélectionner une ressource...",
@@ -1335,6 +1387,14 @@
          "copy": "Copier le jeton",
          "copied": "Jeton copié dans le presse-papiers."
        }
+      },
+      "scheduling": {
+        "findATime": "Trouver un créneau",
+        "previousDay": "Jour précédent",
+        "nextDay": "Jour suivant",
+        "noConflicts": "Aucun conflit",
+        "conflicts": "{{count}} conflit(s)",
+        "addAttendeesToSeeAvailability": "Ajoutez des participants pour voir les disponibilités"
      }
    }
  },
@@ -1401,7 +1461,28 @@
      "logout": "Uitloggen",
      "login": "Inloggen",
      "my_account": "Mijn account",
-      "settings": "Instellingen",
+      "settings": {
+        "label": "Instellingen",
+        "workingHours": {
+          "title": "Werkuren",
+          "description": "Stel uw beschikbare uren in voor planning",
+          "when": "Wanneer",
+          "everyMonday": "Elke maandag",
+          "everyTuesday": "Elke dinsdag",
+          "everyWednesday": "Elke woensdag",
+          "everyThursday": "Elke donderdag",
+          "everyFriday": "Elke vrijdag",
+          "everySaturday": "Elke zaterdag",
+          "everySunday": "Elke zondag",
+          "specificDate": "Specifieke datum...",
+          "start": "Start",
+          "end": "Einde",
+          "addAvailability": "Beschikbaarheid toevoegen",
+          "removeAvailability": "Verwijderen",
+          "save": "Opslaan",
+          "saved": "Werkuren opgeslagen"
+        }
+      },
      "api": {
        "error": {
          "unexpected": "Er is een onverwachte fout opgetreden."
@@ -1715,7 +1796,8 @@
          "participants": "Deelnemers",
          "organizer": "Organisator",
          "viewProfile": "Profiel bekijken",
-          "cannotRemoveOrganizer": "Kan organisator niet verwijderen"
+          "cannotRemoveOrganizer": "Kan organisator niet verwijderen",
+          "noResults": "Geen gebruikers gevonden"
        },
        "resources": {
          "placeholder": "Selecteer een middel...",
@@ -1898,6 +1980,14 @@
          "copy": "Token kopiëren",
          "copied": "Token gekopieerd naar klembord."
        }
+      },
+      "scheduling": {
+        "findATime": "Zoek een tijdstip",
+        "previousDay": "Vorige dag",
+        "nextDay": "Volgende dag",
+        "noConflicts": "Geen conflicten",
+        "conflicts": "{{count}} conflict(en)",
+        "addAttendeesToSeeAvailability": "Voeg deelnemers toe om beschikbaarheid te zien"
      }
    }
  }
--- a/src/frontend/apps/calendars/src/features/layouts/components/header/Header.tsx
+++ b/src/frontend/apps/calendars/src/features/layouts/components/header/Header.tsx
@@ -43,13 +43,10 @@ const ApplicationMenu = () => {
  const router = useRouter();
  const { user } = useAuth();

-  if (!user?.can_admin) return null;
+  if (!user) return null;

-  return (
-    <DropdownMenu
-      isOpen={isOpen}
-      onOpenChange={setIsOpen}
-      options={[
+  const adminOptions = user.can_admin
+    ? [
        {
          label: t("resources.title"),
          icon: <Icon name="meeting_room" type={IconType.OUTLINED} />,
@@ -60,12 +57,26 @@ const ApplicationMenu = () => {
          icon: <Icon name="integration_instructions" type={IconType.OUTLINED} />,
          callback: () => void router.push("/integrations"),
        },
+      ]
+    : [];
+
+  return (
+    <DropdownMenu
+      isOpen={isOpen}
+      onOpenChange={setIsOpen}
+      options={[
+        {
+          label: t("settings.workingHours.title"),
+          icon: <Icon name="schedule" type={IconType.OUTLINED} />,
+          callback: () => void router.push("/settings"),
+        },
+        ...adminOptions,
      ]}
    >
      <Button
        onClick={() => setIsOpen(true)}
        icon={<Icon name="settings" type={IconType.OUTLINED} />}
-        aria-label={t("settings")}
+        aria-label={t("settings.label")}
        color="brand"
        variant="tertiary"
      />
--- a/src/frontend/apps/calendars/src/features/settings/tests/availability-ics.test.ts
+++ b/src/frontend/apps/calendars/src/features/settings/tests/availability-ics.test.ts
@@ -0,0 +1,157 @@
+import {
+  slotsToVCalendar,
+  vCalendarToSlots,
+} from "../availability-ics";
+import type { AvailabilitySlots } from "../types";
+
+describe("availability-ics", () => {
+  describe("slotsToVCalendar", () => {
+    it("converts recurring weekday slots to VCALENDAR", () => {
+      const slots: AvailabilitySlots = [
+        { id: "1", when: { type: "recurring", day: "monday" }, start: "09:00", end: "17:00" },
+        { id: "2", when: { type: "recurring", day: "friday" }, start: "09:00", end: "17:00" },
+      ];
+      const result = slotsToVCalendar(slots);
+      expect(result).toContain("BEGIN:VCALENDAR");
+      expect(result).toContain("BEGIN:VAVAILABILITY");
+      expect(result).toContain("RRULE:FREQ=WEEKLY;BYDAY=MO,FR");
+      expect(result).toContain("T090000");
+      expect(result).toContain("T170000");
+    });
+
+    it("creates separate blocks for different time ranges", () => {
+      const slots: AvailabilitySlots = [
+        { id: "1", when: { type: "recurring", day: "monday" }, start: "09:00", end: "12:00" },
+        { id: "2", when: { type: "recurring", day: "monday" }, start: "14:00", end: "18:00" },
+      ];
+      const result = slotsToVCalendar(slots);
+      const count = (result.match(/BEGIN:AVAILABLE/g) || []).length;
+      expect(count).toBe(2);
+    });
+
+    it("handles specific-date slots without RRULE", () => {
+      const slots: AvailabilitySlots = [
+        { id: "1", when: { type: "specific", date: "2026-03-15" }, start: "10:00", end: "14:00" },
+      ];
+      const result = slotsToVCalendar(slots);
+      expect(result).toContain("DTSTART:20260315T100000");
+      expect(result).toContain("DTEND:20260315T140000");
+      expect(result).not.toContain("RRULE");
+    });
+
+    it("handles mixed recurring and specific-date slots", () => {
+      const slots: AvailabilitySlots = [
+        { id: "1", when: { type: "recurring", day: "tuesday" }, start: "09:00", end: "17:00" },
+        { id: "2", when: { type: "specific", date: "2026-04-01" }, start: "10:00", end: "15:00" },
+      ];
+      const result = slotsToVCalendar(slots);
+      expect(result).toContain("RRULE:FREQ=WEEKLY;BYDAY=TU");
+      expect(result).toContain("DTSTART:20260401T100000");
+      expect(result).not.toMatch(/RRULE.*\n.*20260401/);
+    });
+
+    it("handles empty slots array", () => {
+      const result = slotsToVCalendar([]);
+      expect(result).toContain("BEGIN:VAVAILABILITY");
+      expect(result).not.toContain("BEGIN:AVAILABLE");
+    });
+  });
+
+  describe("vCalendarToSlots", () => {
+    it("parses recurring AVAILABLE blocks into slots", () => {
+      const vcal = `BEGIN:VCALENDAR
+BEGIN:VAVAILABILITY
+BEGIN:AVAILABLE
+DTSTART:20260105T090000
+DTEND:20260105T170000
+RRULE:FREQ=WEEKLY;BYDAY=MO,WE,FR
+END:AVAILABLE
+END:VAVAILABILITY
+END:VCALENDAR`;
+      const result = vCalendarToSlots(vcal);
+      expect(result).toHaveLength(3);
+      expect(result.map((s) => (s.when as { day: string }).day)).toEqual([
+        "monday", "wednesday", "friday",
+      ]);
+      expect(result[0].start).toBe("09:00");
+      expect(result[0].end).toBe("17:00");
+    });
+
+    it("parses specific-date AVAILABLE blocks", () => {
+      const vcal = `BEGIN:VCALENDAR
+BEGIN:VAVAILABILITY
+BEGIN:AVAILABLE
+DTSTART:20260315T100000
+DTEND:20260315T140000
+END:AVAILABLE
+END:VAVAILABILITY
+END:VCALENDAR`;
+      const result = vCalendarToSlots(vcal);
+      expect(result).toHaveLength(1);
+      expect(result[0].when).toEqual({ type: "specific", date: "2026-03-15" });
+      expect(result[0].start).toBe("10:00");
+      expect(result[0].end).toBe("14:00");
+    });
+
+    it("round-trips recurring slots", () => {
+      const original: AvailabilitySlots = [
+        { id: "1", when: { type: "recurring", day: "monday" }, start: "08:00", end: "12:00" },
+        { id: "2", when: { type: "recurring", day: "monday" }, start: "14:00", end: "18:00" },
+        { id: "3", when: { type: "recurring", day: "wednesday" }, start: "09:00", end: "17:00" },
+      ];
+      const vcal = slotsToVCalendar(original);
+      const parsed = vCalendarToSlots(vcal);
+
+      expect(parsed).toHaveLength(3);
+      // Check monday slots
+      const monSlots = parsed.filter(
+        (s) => s.when.type === "recurring" && s.when.day === "monday",
+      );
+      expect(monSlots).toHaveLength(2);
+      expect(monSlots.map((s) => s.start).sort()).toEqual(["08:00", "14:00"]);
+    });
+
+    it("round-trips specific-date slots", () => {
+      const original: AvailabilitySlots = [
+        { id: "1", when: { type: "specific", date: "2026-12-25" }, start: "10:00", end: "14:00" },
+      ];
+      const vcal = slotsToVCalendar(original);
+      const parsed = vCalendarToSlots(vcal);
+      expect(parsed).toHaveLength(1);
+      expect(parsed[0].when).toEqual({ type: "specific", date: "2026-12-25" });
+      expect(parsed[0].start).toBe("10:00");
+      expect(parsed[0].end).toBe("14:00");
+    });
+
+    it("returns empty array for invalid input", () => {
+      expect(vCalendarToSlots("not valid ics")).toEqual([]);
+    });
+
+    it("returns empty array for VCALENDAR with no AVAILABLE", () => {
+      const vcal = `BEGIN:VCALENDAR\nBEGIN:VAVAILABILITY\nEND:VAVAILABILITY\nEND:VCALENDAR`;
+      expect(vCalendarToSlots(vcal)).toEqual([]);
+    });
+
+    it("filters out past specific dates on parse", () => {
+      const vcal = `BEGIN:VCALENDAR
+BEGIN:VAVAILABILITY
+BEGIN:AVAILABLE
+DTSTART:20200101T090000
+DTEND:20200101T170000
+END:AVAILABLE
+END:VAVAILABILITY
+END:VCALENDAR`;
+      expect(vCalendarToSlots(vcal)).toEqual([]);
+    });
+
+    it("filters out past specific dates on save", () => {
+      const slots: AvailabilitySlots = [
+        { id: "1", when: { type: "specific", date: "2020-01-01" }, start: "09:00", end: "17:00" },
+        { id: "2", when: { type: "recurring", day: "monday" }, start: "09:00", end: "17:00" },
+      ];
+      const result = slotsToVCalendar(slots);
+      expect(result).not.toContain("20200101");
+      expect(result).toContain("BYDAY=MO");
+    });
+  });
+});
--- a/src/frontend/apps/calendars/src/features/settings/api/useWorkingHours.ts
+++ b/src/frontend/apps/calendars/src/features/settings/api/useWorkingHours.ts
@@ -0,0 +1,93 @@
+import { useEffect, useMemo, useState } from "react";
+import {
+  useMutation,
+  useQuery,
+  useQueryClient,
+} from "@tanstack/react-query";
+
+import { CalDavService } from "@/features/calendar/services/dav/CalDavService";
+import {
+  caldavServerUrl,
+  headers,
+  fetchOptions,
+} from "@/features/calendar/utils/DavClient";
+import { useAuth } from "@/features/auth/Auth";
+
+import {
+  DEFAULT_AVAILABILITY,
+  type AvailabilitySlots,
+} from "../types";
+import {
+  slotsToVCalendar,
+  vCalendarToSlots,
+} from "../availability-ics";
+
+const WORKING_HOURS_KEY = ["working-hours"];
+
+export const useWorkingHours = () => {
+  const { user } = useAuth();
+  const queryClient = useQueryClient();
+  const caldavService = useMemo(() => new CalDavService(), []);
+  const [isConnected, setIsConnected] = useState(false);
+
+  useEffect(() => {
+    if (!user) return;
+    let cancelled = false;
+
+    caldavService
+      .connect({ serverUrl: caldavServerUrl, headers, fetchOptions })
+      .then((result) => {
+        if (!cancelled && result.success) {
+          setIsConnected(true);
+        }
+      })
+      .catch((err) => {
+        console.error("Failed to connect to CalDAV:", err);
+      });
+
+    return () => {
+      cancelled = true;
+    };
+  }, [caldavService, user]);
+
+  const query = useQuery({
+    queryKey: WORKING_HOURS_KEY,
+    queryFn: async (): Promise<AvailabilitySlots> => {
+      const result = await caldavService.getAvailability();
+      if (
+        !result.success ||
+        typeof result.data !== "string" ||
+        !result.data.includes("VAVAILABILITY")
+      ) {
+        return DEFAULT_AVAILABILITY;
+      }
+      const slots = vCalendarToSlots(result.data);
+      return slots.length > 0 ? slots : DEFAULT_AVAILABILITY;
+    },
+    enabled: isConnected,
+  });
+
+  const mutation = useMutation({
+    mutationFn: async (slots: AvailabilitySlots) => {
+      const vcalendar = slotsToVCalendar(slots);
+      const result = await caldavService.setAvailability(vcalendar);
+      if (!result.success) {
+        throw new Error(
+          result.error ?? "Failed to save availability",
+        );
+      }
+    },
+    onSuccess: () => {
+      void queryClient.invalidateQueries({
+        queryKey: WORKING_HOURS_KEY,
+      });
+    },
+  });
+
+  return {
+    slots: query.data ?? DEFAULT_AVAILABILITY,
+    isLoading: !isConnected || query.isLoading,
+    save: mutation.mutateAsync,
+    isSaving: mutation.isPending,
+  };
+};
--- a/src/frontend/apps/calendars/src/features/settings/availability-ics.ts
+++ b/src/frontend/apps/calendars/src/features/settings/availability-ics.ts
@@ -0,0 +1,164 @@
+import type { DayOfWeek, AvailabilitySlots } from "./types";
+import { generateSlotId } from "./types";
+
+/** Map day names to iCal BYDAY abbreviations */
+const DAY_TO_ICAL: Record<DayOfWeek, string> = {
+  monday: "MO",
+  tuesday: "TU",
+  wednesday: "WE",
+  thursday: "TH",
+  friday: "FR",
+  saturday: "SA",
+  sunday: "SU",
+};
+
+/** Reverse map: iCal abbreviation to day name */
+const ICAL_TO_DAY: Record<string, DayOfWeek> = Object.fromEntries(
+  Object.entries(DAY_TO_ICAL).map(([k, v]) => [v, k as DayOfWeek]),
+) as Record<string, DayOfWeek>;
+
+/**
+ * Anchor dates for each weekday (week of 2026-01-05, a Monday).
+ * Used as DTSTART reference for recurring AVAILABLE components.
+ */
+const DAY_ANCHORS: Record<DayOfWeek, string> = {
+  monday: "20260105",
+  tuesday: "20260106",
+  wednesday: "20260107",
+  thursday: "20260108",
+  friday: "20260109",
+  saturday: "20260110",
+  sunday: "20260111",
+};
+
+/**
+ * Convert AvailabilitySlots to a VCALENDAR string with VAVAILABILITY.
+ *
+ * Groups recurring slots with identical time ranges into single
+ * AVAILABLE components with multi-day BYDAY rules.
+ * Specific-date slots each get their own AVAILABLE block without RRULE.
+ */
+export function slotsToVCalendar(slots: AvailabilitySlots): string {
+  // Separate recurring vs specific
+  const recurringSlots = slots.filter(
+    (s) => s.when.type === "recurring",
+  );
+  const specificSlots = slots.filter(
+    (s) => s.when.type === "specific",
+  );
+
+  // Group recurring by time range
+  const groups = new Map<
+    string,
+    { days: DayOfWeek[]; start: string; end: string }
+  >();
+  for (const slot of recurringSlots) {
+    if (slot.when.type !== "recurring") continue;
+    const key = `${slot.start}-${slot.end}`;
+    const group = groups.get(key);
+    if (group) {
+      group.days.push(slot.when.day);
+    } else {
+      groups.set(key, {
+        days: [slot.when.day],
+        start: slot.start,
+        end: slot.end,
+      });
+    }
+  }
+
+  const blocks: string[] = [];
+
+  // Recurring blocks
+  for (const { days, start, end } of groups.values()) {
+    const byDay = days.map((d) => DAY_TO_ICAL[d]).join(",");
+    const anchor = DAY_ANCHORS[days[0]];
+    const startTime = start.replace(":", "");
+    const endTime = end.replace(":", "");
+    blocks.push(`BEGIN:AVAILABLE
+DTSTART:${anchor}T${startTime}00
+DTEND:${anchor}T${endTime}00
+RRULE:FREQ=WEEKLY;BYDAY=${byDay}
+END:AVAILABLE`);
+  }
+
+  // Specific-date blocks (skip past dates)
+  const today = new Date().toISOString().slice(0, 10);
+  for (const slot of specificSlots) {
+    if (slot.when.type !== "specific") continue;
+    if (slot.when.date < today) continue;
+    const dateStr = slot.when.date.replace(/-/g, "");
+    const startTime = slot.start.replace(":", "");
+    const endTime = slot.end.replace(":", "");
+    blocks.push(`BEGIN:AVAILABLE
+DTSTART:${dateStr}T${startTime}00
+DTEND:${dateStr}T${endTime}00
+END:AVAILABLE`);
+  }
+
+  const inner = blocks.length > 0 ? "\n" + blocks.join("\n") + "\n" : "\n";
+
+  return `BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Calendars//Working Hours//EN
+BEGIN:VAVAILABILITY${inner}END:VAVAILABILITY
+END:VCALENDAR`;
+}
+
+/**
+ * Parse a VCALENDAR with VAVAILABILITY back into AvailabilitySlots.
+ */
+export function vCalendarToSlots(vcalendar: string): AvailabilitySlots {
+  const slots: AvailabilitySlots = [];
+
+  const availableRegex = /BEGIN:AVAILABLE[\s\S]*?END:AVAILABLE/g;
+  let match;
+
+  while ((match = availableRegex.exec(vcalendar)) !== null) {
+    const block = match[0];
+
+    const startMatch = block.match(
+      /DTSTART:(\d{4})(\d{2})(\d{2})T(\d{2})(\d{2})\d{2}/,
+    );
+    const endMatch = block.match(
+      /DTEND:\d{8}T(\d{2})(\d{2})\d{2}/,
+    );
+
+    if (!startMatch || !endMatch) continue;
+
+    const start = `${startMatch[4]}:${startMatch[5]}`;
+    const end = `${endMatch[1]}:${endMatch[2]}`;
+    const dateStr = `${startMatch[1]}-${startMatch[2]}-${startMatch[3]}`;
+
+    const byDayMatch = block.match(/BYDAY=([A-Z,]+)/);
+
+    if (byDayMatch) {
+      // Recurring: create one slot per day in the BYDAY list
+      const days = byDayMatch[1].split(",");
+      for (const icalDay of days) {
+        const dayName = ICAL_TO_DAY[icalDay];
+        if (dayName) {
+          slots.push({
+            id: generateSlotId(),
+            when: { type: "recurring", day: dayName },
+            start,
+            end,
+          });
+        }
+      }
+    } else {
+      // Specific date — skip past dates
+      const today = new Date().toISOString().slice(0, 10);
+      if (dateStr < today) continue;
+
+      slots.push({
+        id: generateSlotId(),
+        when: { type: "specific", date: dateStr },
+        start,
+        end,
+      });
+    }
+  }
+
+  return slots;
+}
--- a/src/frontend/apps/calendars/src/features/settings/components/AvailabilityRow.tsx
+++ b/src/frontend/apps/calendars/src/features/settings/components/AvailabilityRow.tsx
@@ -0,0 +1,102 @@
+import { useCallback } from "react";
+import { useTranslation } from "react-i18next";
+
+import {
+  DAYS_OF_WEEK,
+  type AvailabilitySlot,
+  type AvailabilityWhen,
+  type DayOfWeek,
+} from "../types";
+
+interface AvailabilityRowProps {
+  slot: AvailabilitySlot;
+  onChange: (id: string, updates: Partial<AvailabilitySlot>) => void;
+  onDelete: (id: string) => void;
+}
+
+export const AvailabilityRow = ({
+  slot,
+  onChange,
+  onDelete,
+}: AvailabilityRowProps) => {
+  const { t } = useTranslation();
+
+  const selectValue =
+    slot.when.type === "recurring" ? slot.when.day : "specific";
+
+  const handleWhenChange = useCallback(
+    (value: string) => {
+      let when: AvailabilityWhen;
+      if (value === "specific") {
+        // Default to today's date
+        const today = new Date().toISOString().split("T")[0];
+        when = { type: "specific", date: today };
+      } else {
+        when = { type: "recurring", day: value as DayOfWeek };
+      }
+      onChange(slot.id, { when });
+    },
+    [onChange, slot.id],
+  );
+
+  const handleDateChange = useCallback(
+    (date: string) => {
+      onChange(slot.id, {
+        when: { type: "specific", date },
+      });
+    },
+    [onChange, slot.id],
+  );
+
+  return (
+    <div className="working-hours__row">
+      <div className="working-hours__row-when">
+        <select
+          className="working-hours__select"
+          value={selectValue}
+          onChange={(e) => handleWhenChange(e.target.value)}
+        >
+          {DAYS_OF_WEEK.map((day) => (
+            <option key={day} value={day}>
+              {t(`settings.workingHours.every${day.charAt(0).toUpperCase() + day.slice(1)}`)}
+            </option>
+          ))}
+          <option value="specific">
+            {t("settings.workingHours.specificDate")}
+          </option>
+        </select>
+        {slot.when.type === "specific" && (
+          <input
+            type="date"
+            className="working-hours__date-input"
+            value={slot.when.date}
+            onChange={(e) => handleDateChange(e.target.value)}
+          />
+        )}
+      </div>
+
+      <input
+        type="time"
+        className="working-hours__row-time"
+        value={slot.start}
+        onChange={(e) => onChange(slot.id, { start: e.target.value })}
+      />
+
+      <input
+        type="time"
+        className="working-hours__row-time"
+        value={slot.end}
+        onChange={(e) => onChange(slot.id, { end: e.target.value })}
+      />
+
+      <button
+        type="button"
+        className="working-hours__row-delete"
+        onClick={() => onDelete(slot.id)}
+        aria-label={t("settings.workingHours.removeAvailability")}
+      >
+        <span className="material-icons">close</span>
+      </button>
+    </div>
+  );
+};
--- a/src/frontend/apps/calendars/src/features/settings/components/WorkingHoursSettings.scss
+++ b/src/frontend/apps/calendars/src/features/settings/components/WorkingHoursSettings.scss
@@ -0,0 +1,150 @@
+.settings-page {
+  max-width: 900px;
+  margin: 0 auto;
+  padding: var(--c--globals--spacings--base);
+}
+
+.working-hours {
+  &__header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: var(--c--globals--spacings--xs);
+
+    h2 {
+      margin: 0;
+      font-size: 1.5rem;
+    }
+  }
+
+  &__title-row {
+    display: flex;
+    align-items: center;
+    gap: var(--c--globals--spacings--xs);
+  }
+
+  &__description {
+    color: var(--c--contextuals--content--semantic--neutral--tertiary);
+    margin-bottom: var(--c--globals--spacings--base);
+  }
+
+  &__grid {
+    display: flex;
+    flex-direction: column;
+    gap: var(--c--globals--spacings--2xs);
+  }
+
+  &__grid-header {
+    display: grid;
+    grid-template-columns: 1fr 120px 120px 36px;
+    gap: var(--c--globals--spacings--sm);
+    padding: var(--c--globals--spacings--xs) var(--c--globals--spacings--sm);
+    font-weight: 600;
+    font-size: 0.85rem;
+    color: var(--c--contextuals--content--semantic--neutral--tertiary);
+  }
+
+  &__row {
+    display: grid;
+    grid-template-columns: 1fr 120px 120px 36px;
+    gap: var(--c--globals--spacings--sm);
+    align-items: center;
+    padding: var(--c--globals--spacings--xs) var(--c--globals--spacings--sm);
+    border: 1px solid var(--c--contextuals--border--semantic--neutral--secondary);
+    border-radius: 8px;
+    transition: box-shadow 0.15s ease;
+
+    &:hover {
+      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
+    }
+  }
+
+  &__row-when {
+    display: flex;
+    align-items: center;
+    gap: var(--c--globals--spacings--xs);
+    min-width: 0;
+  }
+
+  &__select {
+    flex: 1;
+    min-width: 0;
+    padding: var(--c--globals--spacings--2xs) var(--c--globals--spacings--xs);
+    border: 1px solid var(--c--contextuals--border--semantic--neutral--secondary);
+    border-radius: 6px;
+    font-size: 0.9rem;
+    background: var(--c--contextuals--background--surface--primary);
+    color: var(--c--contextuals--content--semantic--neutral--primary);
+    cursor: pointer;
+  }
+
+  &__date-input {
+    width: 140px;
+    padding: var(--c--globals--spacings--2xs) var(--c--globals--spacings--xs);
+    border: 1px solid var(--c--contextuals--border--semantic--neutral--secondary);
+    border-radius: 6px;
+    font-size: 0.9rem;
+    background: var(--c--contextuals--background--surface--primary);
+    color: var(--c--contextuals--content--semantic--neutral--primary);
+  }
+
+  &__row-time {
+    padding: var(--c--globals--spacings--2xs) var(--c--globals--spacings--xs);
+    border: 1px solid var(--c--contextuals--border--semantic--neutral--secondary);
+    border-radius: 6px;
+    font-size: 0.9rem;
+    background: var(--c--contextuals--background--surface--primary);
+    color: var(--c--contextuals--content--semantic--neutral--primary);
+  }
+
+  &__row-delete {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    width: 32px;
+    height: 32px;
+    border: none;
+    border-radius: 50%;
+    background: none;
+    cursor: pointer;
+    color: var(--c--contextuals--content--semantic--neutral--tertiary);
+    padding: 0;
+
+    &:hover {
+      background-color: var(--c--contextuals--background--surface--secondary);
+      color: var(--c--contextuals--content--semantic--danger--primary);
+    }
+
+    .material-icons {
+      font-size: 18px;
+    }
+  }
+
+  &__add-row {
+    margin-top: var(--c--globals--spacings--xs);
+  }
+
+  &__actions {
+    display: flex;
+    justify-content: flex-end;
+    margin-top: var(--c--globals--spacings--base);
+  }
+
+  &__loading {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    padding: var(--c--globals--spacings--xl) 0;
+    color: var(--c--contextuals--content--semantic--neutral--tertiary);
+
+    .material-icons {
+      font-size: 48px;
+      margin-bottom: var(--c--globals--spacings--sm);
+    }
+  }
+
+  &__spinner {
+    animation: spin 1.5s linear infinite;
+  }
+}
--- a/src/frontend/apps/calendars/src/features/settings/components/WorkingHoursSettings.tsx
+++ b/src/frontend/apps/calendars/src/features/settings/components/WorkingHoursSettings.tsx
@@ -0,0 +1,161 @@
+import { useCallback, useState } from "react";
+import { useTranslation } from "react-i18next";
+import { Button } from "@gouvfr-lasuite/cunningham-react";
+import { useRouter } from "next/router";
+
+import {
+  addToast,
+  ToasterItem,
+} from "@/features/ui/components/toaster/Toaster";
+
+import { useWorkingHours } from "../api/useWorkingHours";
+import {
+  type AvailabilitySlot,
+  type AvailabilitySlots,
+  generateSlotId,
+} from "../types";
+import { AvailabilityRow } from "./AvailabilityRow";
+
+interface AvailabilityFormProps {
+  initialSlots: AvailabilitySlots;
+  onSave: (slots: AvailabilitySlots) => Promise<void>;
+  isSaving: boolean;
+}
+
+const AvailabilityForm = ({
+  initialSlots,
+  onSave,
+  isSaving,
+}: AvailabilityFormProps) => {
+  const { t } = useTranslation();
+  const router = useRouter();
+
+  const [slots, setSlots] = useState<AvailabilitySlots>(initialSlots);
+
+  const addSlot = useCallback(() => {
+    setSlots((prev) => [
+      ...prev,
+      {
+        id: generateSlotId(),
+        when: { type: "recurring", day: "monday" },
+        start: "09:00",
+        end: "18:00",
+      },
+    ]);
+  }, []);
+
+  const removeSlot = useCallback((id: string) => {
+    setSlots((prev) => prev.filter((s) => s.id !== id));
+  }, []);
+
+  const updateSlot = useCallback(
+    (id: string, updates: Partial<AvailabilitySlot>) => {
+      setSlots((prev) =>
+        prev.map((s) => (s.id === id ? { ...s, ...updates } : s)),
+      );
+    },
+    [],
+  );
+
+  const handleSave = async () => {
+    try {
+      await onSave(slots);
+      addToast(
+        <ToasterItem type="info">
+          <span>{t("settings.workingHours.saved")}</span>
+        </ToasterItem>,
+      );
+    } catch {
+      addToast(
+        <ToasterItem type="error">
+          <span>{t("api.error.unexpected")}</span>
+        </ToasterItem>,
+      );
+    }
+  };
+
+  return (
+    <div className="working-hours">
+      <div className="working-hours__header">
+        <div className="working-hours__title-row">
+          <Button
+            color="neutral"
+            size="small"
+            icon={
+              <span className="material-icons">arrow_back</span>
+            }
+            onClick={() => void router.push("/calendar")}
+            aria-label={t("app_title")}
+          />
+          <h2>{t("settings.workingHours.title")}</h2>
+        </div>
+      </div>
+
+      <p className="working-hours__description">
+        {t("settings.workingHours.description")}
+      </p>
+
+      <div className="working-hours__grid">
+        <div className="working-hours__grid-header">
+          <span>{t("settings.workingHours.when")}</span>
+          <span>{t("settings.workingHours.start")}</span>
+          <span>{t("settings.workingHours.end")}</span>
+          <span />
+        </div>
+
+        {slots.map((slot) => (
+          <AvailabilityRow
+            key={slot.id}
+            slot={slot}
+            onChange={updateSlot}
+            onDelete={removeSlot}
+          />
+        ))}
+      </div>
+
+      <div className="working-hours__add-row">
+        <Button
+          color="neutral"
+          size="small"
+          icon={<span className="material-icons">add</span>}
+          onClick={addSlot}
+        >
+          {t("settings.workingHours.addAvailability")}
+        </Button>
+      </div>
+
+      <div className="working-hours__actions">
+        <Button
+          color="brand"
+          onClick={() => void handleSave()}
+          disabled={isSaving}
+        >
+          {t("settings.workingHours.save")}
+        </Button>
+      </div>
+    </div>
+  );
+};
+
+export const WorkingHoursSettings = () => {
+  const { slots, isLoading, save, isSaving } = useWorkingHours();
+
+  if (isLoading) {
+    return (
+      <div className="working-hours__loading">
+        <span className="material-icons working-hours__spinner">
+          hourglass_empty
+        </span>
+      </div>
+    );
+  }
+
+  return (
+    <AvailabilityForm
+      key={JSON.stringify(slots)}
+      initialSlots={slots}
+      onSave={save}
+      isSaving={isSaving}
+    />
+  );
+};
--- a/src/frontend/apps/calendars/src/features/settings/types.ts
+++ b/src/frontend/apps/calendars/src/features/settings/types.ts
@@ -0,0 +1,46 @@
+export interface DaySchedule {
+  start: string; // "HH:MM" format
+  end: string; // "HH:MM" format
+}
+
+export type DayOfWeek =
+  | "monday"
+  | "tuesday"
+  | "wednesday"
+  | "thursday"
+  | "friday"
+  | "saturday"
+  | "sunday";
+
+export const DAYS_OF_WEEK: DayOfWeek[] = [
+  "monday",
+  "tuesday",
+  "wednesday",
+  "thursday",
+  "friday",
+  "saturday",
+  "sunday",
+];
+
+export type AvailabilityWhen =
+  | { type: "recurring"; day: DayOfWeek }
+  | { type: "specific"; date: string }; // "YYYY-MM-DD"
+
+export interface AvailabilitySlot {
+  id: string;
+  when: AvailabilityWhen;
+  start: string; // "HH:MM"
+  end: string; // "HH:MM"
+}
+
+export type AvailabilitySlots = AvailabilitySlot[];
+
+export const generateSlotId = (): string => crypto.randomUUID();
+
+export const DEFAULT_AVAILABILITY: AvailabilitySlots = [
+  { id: "d-mon", when: { type: "recurring", day: "monday" }, start: "09:00", end: "18:00" },
+  { id: "d-tue", when: { type: "recurring", day: "tuesday" }, start: "09:00", end: "18:00" },
+  { id: "d-wed", when: { type: "recurring", day: "wednesday" }, start: "09:00", end: "18:00" },
+  { id: "d-thu", when: { type: "recurring", day: "thursday" }, start: "09:00", end: "18:00" },
+  { id: "d-fri", when: { type: "recurring", day: "friday" }, start: "09:00", end: "18:00" },
+];
--- a/src/frontend/apps/calendars/src/features/users/hooks/useUserSearch.ts
+++ b/src/frontend/apps/calendars/src/features/users/hooks/useUserSearch.ts
@@ -0,0 +1,44 @@
+import { useState, useEffect } from "react";
+import { useQuery } from "@tanstack/react-query";
+import { fetchAPI } from "@/features/api/fetchApi";
+
+export interface UserSearchResult {
+  id: string;
+  email: string;
+  full_name: string;
+}
+
+interface PaginatedResponse {
+  count: number;
+  next: string | null;
+  previous: string | null;
+  results: UserSearchResult[];
+}
+
+const DEBOUNCE_MS = 300;
+const MIN_QUERY_LENGTH = 3;
+
+function useDebouncedValue(value: string, delay: number): string {
+  const [debounced, setDebounced] = useState(value);
+  useEffect(() => {
+    const timer = setTimeout(() => setDebounced(value), delay);
+    return () => clearTimeout(timer);
+  }, [value, delay]);
+  return debounced;
+}
+
+export const useUserSearch = (query: string) => {
+  const debouncedQuery = useDebouncedValue(query.trim(), DEBOUNCE_MS);
+
+  return useQuery({
+    queryKey: ["users", "search", debouncedQuery],
+    queryFn: async () => {
+      const response = await fetchAPI("users/", {
+        params: { q: debouncedQuery },
+      });
+      const data = (await response.json()) as PaginatedResponse;
+      return data.results;
+    },
+    enabled: debouncedQuery.length >= MIN_QUERY_LENGTH,
+  });
+};
--- a/src/frontend/apps/calendars/src/pages/settings.tsx
+++ b/src/frontend/apps/calendars/src/pages/settings.tsx
@@ -0,0 +1,79 @@
+import { useEffect } from "react";
+
+import { MainLayout } from "@gouvfr-lasuite/ui-kit";
+import Head from "next/head";
+import { useTranslation } from "next-i18next";
+import { useRouter } from "next/router";
+
+import { login, useAuth } from "@/features/auth/Auth";
+import { GlobalLayout } from "@/features/layouts/components/global/GlobalLayout";
+import {
+  HeaderIcon,
+  HeaderRight,
+} from "@/features/layouts/components/header/Header";
+import { SpinnerPage } from "@/features/ui/components/spinner/SpinnerPage";
+import { Toaster } from "@/features/ui/components/toaster/Toaster";
+import { WorkingHoursSettings } from "@/features/settings/components/WorkingHoursSettings";
+
+export default function SettingsPage() {
+  const { t } = useTranslation();
+  const { user } = useAuth();
+  const router = useRouter();
+
+  useEffect(() => {
+    if (!user) {
+      login(window.location.href);
+    } else if (user.can_access === false) {
+      void router.push("/no-access");
+    }
+  }, [user, router]);
+
+  if (!user || user.can_access === false) {
+    return <SpinnerPage />;
+  }
+
+  return (
+    <>
+      <Head>
+        <title>
+          {t("settings.workingHours.title")} -{" "}
+          {t("app_title")}
+        </title>
+        <meta
+          name="description"
+          content={t(
+            "settings.workingHours.description",
+          )}
+        />
+        <meta
+          name="viewport"
+          content="width=device-width, initial-scale=1"
+        />
+        <link rel="icon" href="/favicon.png" />
+      </Head>
+
+      <div className="settings-page">
+        <WorkingHoursSettings />
+      </div>
+
+      <Toaster />
+    </>
+  );
+}
+
+SettingsPage.getLayout = function getLayout(
+  page: React.ReactElement,
+) {
+  return (
+    <GlobalLayout>
+      <MainLayout
+        enableResize={false}
+        hideLeftPanelOnDesktop={true}
+        icon={<HeaderIcon />}
+        rightHeaderContent={<HeaderRight />}
+      >
+        {page}
+      </MainLayout>
+    </GlobalLayout>
+  );
+};
--- a/src/frontend/apps/calendars/src/styles/globals.scss
+++ b/src/frontend/apps/calendars/src/styles/globals.scss
@@ -1,29 +1,31 @@
@use "@gouvfr-lasuite/ui-kit/sass/fonts";
@use "@gouvfr-lasuite/ui-kit/style";
@use "./cunningham-tokens.css";
-@use "./../features/layouts/components/global/GlobalLayout.scss";
-@use "./../features/feedback/Feedback.scss";
-@use "./../features/layouts/components/header/index.scss";
+@use "./../features/layouts/components/global/GlobalLayout";
+@use "./../features/feedback/Feedback";
+@use "./../features/layouts/components/header/index";
@use "./../features/ui/components/toaster";
-@use "./../features/ui/components/generic-disclaimer/GenericDisclaimer.scss";
-@use "./../features/ui/components/spinner/SpinnerPage.scss";
-@use "./../features/ui/components/logo/DynamicCalendarLogo.scss";
-@use "./../features/layouts/components/left-panel/LeftPanelMobile.scss";
-@use "./../features/calendar/components/left-panel/MiniCalendar.scss";
-@use "./../features/calendar/components/calendar-list/CalendarList.scss";
-@use "./../features/calendar/components/left-panel/LeftPanel.scss";
-@use "./../features/calendar/components/scheduler/EventModal.scss";
-@use "./../features/calendar/components/scheduler/RecurrenceEditor.scss";
-@use "./../features/calendar/components/scheduler/AttendeesInput.scss";
-@use "./../features/calendar/components/scheduler/Scheduler.scss";
-@use "./../features/calendar/components/scheduler/scheduler-theme.scss";
-@use "./../features/calendar/components/scheduler/SchedulerToolbar.scss";
-@use "./../features/calendar/components/scheduler/event-modal-sections/SectionRow.scss";
-@use "./../features/calendar/components/scheduler/event-modal-sections/InvitationResponseSection.scss";
-@use "./../features/calendar/components/scheduler/event-modal-sections/SectionPill.scss";
+@use "./../features/ui/components/generic-disclaimer/GenericDisclaimer";
+@use "./../features/ui/components/spinner/SpinnerPage";
+@use "./../features/ui/components/logo/DynamicCalendarLogo";
+@use "./../features/layouts/components/left-panel/LeftPanelMobile";
+@use "./../features/calendar/components/left-panel/MiniCalendar";
+@use "./../features/calendar/components/calendar-list/CalendarList";
+@use "./../features/calendar/components/left-panel/LeftPanel";
+@use "./../features/calendar/components/scheduler/EventModal";
+@use "./../features/calendar/components/scheduler/RecurrenceEditor";
+@use "./../features/calendar/components/scheduler/AttendeesInput";
+@use "./../features/calendar/components/scheduler/Scheduler";
+@use "./../features/calendar/components/scheduler/scheduler-theme";
+@use "./../features/calendar/components/scheduler/SchedulerToolbar";
+@use "./../features/calendar/components/scheduler/event-modal-sections/SectionRow";
+@use "./../features/calendar/components/scheduler/event-modal-sections/InvitationResponseSection";
+@use "./../features/calendar/components/scheduler/event-modal-sections/SectionPill";
+@use "./../features/calendar/components/scheduler/FreeBusyTimeline";
@use "./../features/resources/components/Resources";
-@use "./../pages/index.scss" as *;
-@use "./../pages/calendar.scss" as *;
+@use "./../features/settings/components/WorkingHoursSettings";
+@use "./../pages/index" as *;
+@use "./../pages/calendar" as *;
 html,
 body {
  margin: 0;
--- a/src/frontend/apps/calendars/types.d.ts
+++ b/src/frontend/apps/calendars/types.d.ts
@@ -25,7 +25,6 @@ declare module "@event-calendar/core" {
    updateEvent: (event: unknown) => void;
    removeEventById: (id: string) => void;
    unselect: () => void;
-    $destroy?: () => void;
  }

  export function createCalendar(
@@ -34,6 +33,8 @@ declare module "@event-calendar/core" {
    options: Record<string, unknown>
  ): Calendar;

+  export function destroyCalendar(calendar: Calendar): void;
+
  export const TimeGrid: unknown;
  export const DayGrid: unknown;
  export const List: unknown;