diff --git a/src/backend/core/services/converter_services.py b/src/backend/core/services/converter_services.py
index 56faf1e6..d6a6dbf4 100644
--- a/src/backend/core/services/converter_services.py
+++ b/src/backend/core/services/converter_services.py
@@ -26,7 +26,7 @@ class YdocConverter:
     def auth_header(self):
         """Build microservice authentication header."""
         # Note: Yprovider microservice accepts only raw token, which is not recommended
-        return settings.Y_PROVIDER_API_KEY
+        return f"Bearer {settings.Y_PROVIDER_API_KEY}"
 
     def convert(self, text):
         """Convert a Markdown text into our internal format using an external microservice."""
diff --git a/src/backend/core/tests/test_services_converter_services.py b/src/backend/core/tests/test_services_converter_services.py
index 99be195e..01773f85 100644
--- a/src/backend/core/tests/test_services_converter_services.py
+++ b/src/backend/core/tests/test_services_converter_services.py
@@ -17,7 +17,7 @@ def test_auth_header(settings):
     """Test authentication header generation."""
     settings.Y_PROVIDER_API_KEY = "test-key"
     converter = YdocConverter()
-    assert converter.auth_header == "test-key"
+    assert converter.auth_header == "Bearer test-key"
 
 
 def test_convert_empty_text():
@@ -82,7 +82,7 @@ def test_convert_full_integration(mock_post, settings):
         "http://test.com/conversion-endpoint/",
         data="test markdown",
         headers={
-            "Authorization": "test-key",
+            "Authorization": "Bearer test-key",
             "Content-Type": "text/markdown",
         },
         timeout=5,