diff --git a/src/service/appservice/append.rs b/src/service/appservice/append.rs
new file mode 100644
index 00000000..980ef28f
--- /dev/null
+++ b/src/service/appservice/append.rs
@@ -0,0 +1,103 @@
+use ruma::{UserId, events::TimelineEventType};
+use tuwunel_core::{
+	Result, error, implement,
+	matrix::{
+		event::Event,
+		pdu::{Pdu, RawPduId},
+	},
+	utils::ReadyExt,
+};
+
+use super::{NamespaceRegex, RegistrationInfo};
+
+/// Called by timeline::append() after accepting new PDU.
+#[implement(super::Service)]
+#[tracing::instrument(name = "append", level = "debug", skip_all)]
+pub(crate) async fn append_pdu(&self, pdu_id: RawPduId, pdu: &Pdu) -> Result {
+	for appservice in self.read().await.values() {
+		self.append_pdu_to(appservice, pdu_id, pdu)
+			.await
+			.inspect_err(|e| {
+				error!(
+					event_id = %pdu.event_id(),
+					appservice = ?appservice.registration.id,
+					"Failed to send PDU to appservice: {e}"
+				);
+			})
+			.ok();
+	}
+
+	Ok(())
+}
+
+#[implement(super::Service)]
+#[tracing::instrument(
+	name = "append_to",
+	level = "debug",
+	skip_all,
+	fields(id = %appservice.registration.id),
+)]
+async fn append_pdu_to(
+	&self,
+	appservice: &RegistrationInfo,
+	pdu_id: RawPduId,
+	pdu: &Pdu,
+) -> Result {
+	if self
+		.services
+		.state_cache
+		.appservice_in_room(pdu.room_id(), appservice)
+		.await
+	{
+		self.services
+			.sending
+			.send_pdu_appservice(appservice.registration.id.clone(), pdu_id)?;
+
+		return Ok(());
+	}
+
+	// If the RoomMember event has a non-empty state_key, it is targeted at someone.
+	// If it is our appservice user, we send this PDU to it.
+	if *pdu.kind() == TimelineEventType::RoomMember {
+		if let Some(state_key_uid) = &pdu
+			.state_key
+			.as_ref()
+			.and_then(|state_key| UserId::parse(state_key.as_str()).ok())
+		{
+			let appservice_uid = appservice.registration.sender_localpart.as_str();
+			if state_key_uid == &appservice_uid {
+				self.services
+					.sending
+					.send_pdu_appservice(appservice.registration.id.clone(), pdu_id)?;
+
+				return Ok(());
+			}
+		}
+	}
+
+	let matching_users = |users: &NamespaceRegex| {
+		appservice.users.is_match(pdu.sender().as_str())
+			|| *pdu.kind() == TimelineEventType::RoomMember
+				&& pdu
+					.state_key
+					.as_ref()
+					.is_some_and(|state_key| users.is_match(state_key))
+	};
+	let matching_aliases = |aliases: NamespaceRegex| {
+		self.services
+			.alias
+			.local_aliases_for_room(pdu.room_id())
+			.ready_any(move |room_alias| aliases.is_match(room_alias.as_str()))
+	};
+
+	if matching_aliases(appservice.aliases.clone()).await
+		|| appservice.rooms.is_match(pdu.room_id().as_str())
+		|| matching_users(&appservice.users)
+	{
+		self.services
+			.sending
+			.send_pdu_appservice(appservice.registration.id.clone(), pdu_id)?;
+	}
+
+	Ok(())
+}
diff --git a/src/service/appservice/mod.rs b/src/service/appservice/mod.rs
index b99ed7aa..24382ca3 100644
--- a/src/service/appservice/mod.rs
+++ b/src/service/appservice/mod.rs
@@ -1,3 +1,4 @@
+mod append;
 mod namespace_regex;
 mod registration_info;
 
diff --git a/src/service/rooms/timeline/append.rs b/src/service/rooms/timeline/append.rs
index 3c94bfbd..bbe5a870 100644
--- a/src/service/rooms/timeline/append.rs
+++ b/src/service/rooms/timeline/append.rs
@@ -23,12 +23,12 @@ use tuwunel_core::{
 		event::Event,
 		pdu::{PduCount, PduEvent, PduId, RawPduId},
 	},
-	utils::{self, ReadyExt},
+	utils::{self, ReadyExt, result::LogErr},
 };
 use tuwunel_database::{Json, Map};
 
 use super::{ExtractBody, ExtractRelatesTo, ExtractRelatesToEventId, RoomMutexGuard};
-use crate::{appservice::NamespaceRegex, rooms::state_compressor::CompressedState};
+use crate::rooms::state_compressor::CompressedState;
 
 /// Append the incoming event setting the state snapshot to the state from
 /// the server that sent the event.
@@ -426,63 +426,12 @@ where
 	drop(next_count1);
 	drop(next_count2);
 
-	for appservice in self.services.appservice.read().await.values() {
-		if self
-			.services
-			.state_cache
-			.appservice_in_room(pdu.room_id(), appservice)
-			.await
-		{
-			self.services
-				.sending
-				.send_pdu_appservice(appservice.registration.id.clone(), pdu_id)?;
-
-			continue;
-		}
-
-		// If the RoomMember event has a non-empty state_key, it is targeted at someone.
-		// If it is our appservice user, we send this PDU to it.
-		if *pdu.kind() == TimelineEventType::RoomMember {
-			if let Some(state_key_uid) = &pdu
-				.state_key
-				.as_ref()
-				.and_then(|state_key| UserId::parse(state_key.as_str()).ok())
-			{
-				let appservice_uid = appservice.registration.sender_localpart.as_str();
-				if state_key_uid == &appservice_uid {
-					self.services
-						.sending
-						.send_pdu_appservice(appservice.registration.id.clone(), pdu_id)?;
-
-					continue;
-				}
-			}
-		}
-
-		let matching_users = |users: &NamespaceRegex| {
-			appservice.users.is_match(pdu.sender().as_str())
-				|| *pdu.kind() == TimelineEventType::RoomMember
-					&& pdu
-						.state_key
-						.as_ref()
-						.is_some_and(|state_key| users.is_match(state_key))
-		};
-		let matching_aliases = |aliases: NamespaceRegex| {
-			self.services
-				.alias
-				.local_aliases_for_room(pdu.room_id())
-				.ready_any(move |room_alias| aliases.is_match(room_alias.as_str()))
-		};
-
-		if matching_aliases(appservice.aliases.clone()).await
-			|| appservice.rooms.is_match(pdu.room_id().as_str())
-			|| matching_users(&appservice.users)
-		{
-			self.services
-				.sending
-				.send_pdu_appservice(appservice.registration.id.clone(), pdu_id)?;
-		}
-	}
+	self.services
+		.appservice
+		.append_pdu(pdu_id, pdu)
+		.await
+		.log_err()
+		.ok();
 
 	Ok(pdu_id)
 }