diff --git a/src/api/client/sync/mod.rs b/src/api/client/sync/mod.rs
new file mode 100644
index 00000000..0cfc7b8b
--- /dev/null
+++ b/src/api/client/sync/mod.rs
@@ -0,0 +1,67 @@
+mod v3;
+mod v4;
+
+use conduit::{
+	utils::{math::usize_from_u64_truncated, ReadyExt},
+	PduCount,
+};
+use futures::StreamExt;
+use ruma::{RoomId, UserId};
+
+pub(crate) use self::{v3::sync_events_route, v4::sync_events_v4_route};
+use crate::{service::Services, Error, PduEvent, Result};
+
+async fn load_timeline(
+	services: &Services, sender_user: &UserId, room_id: &RoomId, roomsincecount: PduCount, limit: u64,
+) -> Result<(Vec<(PduCount, PduEvent)>, bool), Error> {
+	let timeline_pdus;
+	let limited = if services
+		.rooms
+		.timeline
+		.last_timeline_count(sender_user, room_id)
+		.await?
+		> roomsincecount
+	{
+		let mut non_timeline_pdus = services
+			.rooms
+			.timeline
+			.pdus_until(sender_user, room_id, PduCount::max())
+			.await?
+			.ready_take_while(|(pducount, _)| pducount > &roomsincecount);
+
+		// Take the last events for the timeline
+		timeline_pdus = non_timeline_pdus
+			.by_ref()
+			.take(usize_from_u64_truncated(limit))
+			.collect::<Vec<_>>()
+			.await
+			.into_iter()
+			.rev()
+			.collect::<Vec<_>>();
+
+		// They /sync response doesn't always return all messages, so we say the output
+		// is limited unless there are events in non_timeline_pdus
+		non_timeline_pdus.next().await.is_some()
+	} else {
+		timeline_pdus = Vec::new();
+		false
+	};
+	Ok((timeline_pdus, limited))
+}
+
+async fn share_encrypted_room(
+	services: &Services, sender_user: &UserId, user_id: &UserId, ignore_room: Option<&RoomId>,
+) -> bool {
+	services
+		.rooms
+		.user
+		.get_shared_rooms(sender_user, user_id)
+		.ready_filter(|&room_id| Some(room_id) != ignore_room)
+		.any(|other_room_id| {
+			services
+				.rooms
+				.state_accessor
+				.is_encrypted_room(other_room_id)
+		})
+		.await
+}
diff --git a/src/api/client/sync.rs b/src/api/client/sync/v3.rs
similarity index 56%
rename from src/api/client/sync.rs
rename to src/api/client/sync/v3.rs
index 65af775d..f29fe220 100644
--- a/src/api/client/sync.rs
+++ b/src/api/client/sync/v3.rs
@@ -1,23 +1,19 @@
 use std::{
-	cmp::{self, Ordering},
-	collections::{hash_map::Entry, BTreeMap, BTreeSet, HashMap, HashSet},
+	cmp::{self},
+	collections::{hash_map::Entry, BTreeMap, HashMap, HashSet},
 	time::Duration,
 };
 
 use axum::extract::State;
 use conduit::{
-	debug, err, error, is_equal_to,
+	err, error, extract_variant, is_equal_to,
 	result::FlatOk,
-	utils::{
-		math::{ruma_from_u64, ruma_from_usize, usize_from_ruma, usize_from_u64_truncated},
-		BoolExt, IterStream, ReadyExt, TryFutureExtExt,
-	},
-	warn, PduCount,
+	utils::{math::ruma_from_u64, BoolExt, IterStream, ReadyExt, TryFutureExtExt},
+	PduCount,
 };
-use futures::{future::OptionFuture, pin_mut, FutureExt, StreamExt, TryFutureExt};
+use futures::{future::OptionFuture, pin_mut, FutureExt, StreamExt};
 use ruma::{
 	api::client::{
-		error::ErrorKind,
 		filter::{FilterDefinition, LazyLoadOptions},
 		sync::sync_events::{
 			self,
@@ -25,43 +21,27 @@ use ruma::{
 				Ephemeral, Filter, GlobalAccountData, InviteState, InvitedRoom, JoinedRoom, LeftRoom, Presence,
 				RoomAccountData, RoomSummary, Rooms, State as RoomState, Timeline, ToDevice,
 			},
-			v4::{SlidingOp, SlidingSyncRoomHero},
 			DeviceLists, UnreadNotificationsCount,
 		},
 		uiaa::UiaaResponse,
 	},
-	directory::RoomTypeFilter,
 	events::{
 		presence::PresenceEvent,
 		room::member::{MembershipState, RoomMemberEventContent},
 		AnyRawAccountDataEvent, StateEventType,
-		TimelineEventType::{self, *},
+		TimelineEventType::*,
 	},
 	serde::Raw,
-	state_res::Event,
-	uint, DeviceId, EventId, MilliSecondsSinceUnixEpoch, OwnedRoomId, OwnedUserId, RoomId, UInt, UserId,
+	uint, DeviceId, EventId, OwnedRoomId, OwnedUserId, RoomId, UserId,
 };
-use service::rooms::read_receipt::pack_receipts;
 use tracing::{Instrument as _, Span};
 
+use super::{load_timeline, share_encrypted_room};
 use crate::{
 	service::{pdu::EventHash, Services},
 	utils, Error, PduEvent, Result, Ruma, RumaResponse,
 };
 
-const SINGLE_CONNECTION_SYNC: &str = "single_connection_sync";
-const DEFAULT_BUMP_TYPES: &[TimelineEventType; 6] =
-	&[RoomMessage, RoomEncrypted, Sticker, CallInvite, PollStart, Beacon];
-
-macro_rules! extract_variant {
-	($e:expr, $variant:path) => {
-		match $e {
-			$variant(value) => Some(value),
-			_ => None,
-		}
-	};
-}
-
 /// # `GET /_matrix/client/r0/sync`
 ///
 /// Synchronize the client's state with the latest state on the server.
@@ -1085,800 +1065,3 @@ async fn load_joined_room(
 		unread_thread_notifications: BTreeMap::new(),
 	})
 }
-
-async fn load_timeline(
-	services: &Services, sender_user: &UserId, room_id: &RoomId, roomsincecount: PduCount, limit: u64,
-) -> Result<(Vec<(PduCount, PduEvent)>, bool), Error> {
-	let timeline_pdus;
-	let limited = if services
-		.rooms
-		.timeline
-		.last_timeline_count(sender_user, room_id)
-		.await?
-		> roomsincecount
-	{
-		let mut non_timeline_pdus = services
-			.rooms
-			.timeline
-			.pdus_until(sender_user, room_id, PduCount::max())
-			.await?
-			.ready_take_while(|(pducount, _)| pducount > &roomsincecount);
-
-		// Take the last events for the timeline
-		timeline_pdus = non_timeline_pdus
-			.by_ref()
-			.take(usize_from_u64_truncated(limit))
-			.collect::<Vec<_>>()
-			.await
-			.into_iter()
-			.rev()
-			.collect::<Vec<_>>();
-
-		// They /sync response doesn't always return all messages, so we say the output
-		// is limited unless there are events in non_timeline_pdus
-		non_timeline_pdus.next().await.is_some()
-	} else {
-		timeline_pdus = Vec::new();
-		false
-	};
-	Ok((timeline_pdus, limited))
-}
-
-async fn share_encrypted_room(
-	services: &Services, sender_user: &UserId, user_id: &UserId, ignore_room: Option<&RoomId>,
-) -> bool {
-	services
-		.rooms
-		.user
-		.get_shared_rooms(sender_user, user_id)
-		.ready_filter(|&room_id| Some(room_id) != ignore_room)
-		.any(|other_room_id| {
-			services
-				.rooms
-				.state_accessor
-				.is_encrypted_room(other_room_id)
-		})
-		.await
-}
-
-/// POST `/_matrix/client/unstable/org.matrix.msc3575/sync`
-///
-/// Sliding Sync endpoint (future endpoint: `/_matrix/client/v4/sync`)
-pub(crate) async fn sync_events_v4_route(
-	State(services): State<crate::State>, body: Ruma<sync_events::v4::Request>,
-) -> Result<sync_events::v4::Response> {
-	let sender_user = body.sender_user.as_ref().expect("user is authenticated");
-	let sender_device = body.sender_device.expect("user is authenticated");
-	let mut body = body.body;
-	// Setup watchers, so if there's no response, we can wait for them
-	let watcher = services.globals.watch(sender_user, &sender_device);
-
-	let next_batch = services.globals.next_count()?;
-
-	let conn_id = body
-		.conn_id
-		.clone()
-		.unwrap_or_else(|| SINGLE_CONNECTION_SYNC.to_owned());
-
-	let globalsince = body
-		.pos
-		.as_ref()
-		.and_then(|string| string.parse().ok())
-		.unwrap_or(0);
-
-	if globalsince != 0
-		&& !services
-			.sync
-			.remembered(sender_user.clone(), sender_device.clone(), conn_id.clone())
-	{
-		debug!("Restarting sync stream because it was gone from the database");
-		return Err(Error::Request(
-			ErrorKind::UnknownPos,
-			"Connection data lost since last time".into(),
-			http::StatusCode::BAD_REQUEST,
-		));
-	}
-
-	if globalsince == 0 {
-		services
-			.sync
-			.forget_sync_request_connection(sender_user.clone(), sender_device.clone(), conn_id.clone());
-	}
-
-	// Get sticky parameters from cache
-	let known_rooms =
-		services
-			.sync
-			.update_sync_request_with_cache(sender_user.clone(), sender_device.clone(), &mut body);
-
-	let all_joined_rooms: Vec<_> = services
-		.rooms
-		.state_cache
-		.rooms_joined(sender_user)
-		.map(ToOwned::to_owned)
-		.collect()
-		.await;
-
-	let all_invited_rooms: Vec<_> = services
-		.rooms
-		.state_cache
-		.rooms_invited(sender_user)
-		.map(|r| r.0)
-		.collect()
-		.await;
-
-	let all_rooms = all_joined_rooms
-		.iter()
-		.chain(all_invited_rooms.iter())
-		.map(Clone::clone)
-		.collect();
-
-	if body.extensions.to_device.enabled.unwrap_or(false) {
-		services
-			.users
-			.remove_to_device_events(sender_user, &sender_device, globalsince)
-			.await;
-	}
-
-	let mut left_encrypted_users = HashSet::new(); // Users that have left any encrypted rooms the sender was in
-	let mut device_list_changes = HashSet::new();
-	let mut device_list_left = HashSet::new();
-
-	let mut receipts = sync_events::v4::Receipts {
-		rooms: BTreeMap::new(),
-	};
-
-	let mut account_data = sync_events::v4::AccountData {
-		global: Vec::new(),
-		rooms: BTreeMap::new(),
-	};
-	if body.extensions.account_data.enabled.unwrap_or(false) {
-		account_data.global = services
-			.account_data
-			.changes_since(None, sender_user, globalsince)
-			.await?
-			.into_iter()
-			.filter_map(|e| extract_variant!(e, AnyRawAccountDataEvent::Global))
-			.collect();
-
-		if let Some(rooms) = body.extensions.account_data.rooms {
-			for room in rooms {
-				account_data.rooms.insert(
-					room.clone(),
-					services
-						.account_data
-						.changes_since(Some(&room), sender_user, globalsince)
-						.await?
-						.into_iter()
-						.filter_map(|e| extract_variant!(e, AnyRawAccountDataEvent::Room))
-						.collect(),
-				);
-			}
-		}
-	}
-
-	if body.extensions.e2ee.enabled.unwrap_or(false) {
-		// Look for device list updates of this account
-		device_list_changes.extend(
-			services
-				.users
-				.keys_changed(sender_user.as_ref(), globalsince, None)
-				.map(ToOwned::to_owned)
-				.collect::<Vec<_>>()
-				.await,
-		);
-
-		for room_id in &all_joined_rooms {
-			let Ok(current_shortstatehash) = services.rooms.state.get_room_shortstatehash(room_id).await else {
-				error!("Room {room_id} has no state");
-				continue;
-			};
-
-			let since_shortstatehash = services
-				.rooms
-				.user
-				.get_token_shortstatehash(room_id, globalsince)
-				.await
-				.ok();
-
-			let encrypted_room = services
-				.rooms
-				.state_accessor
-				.state_get(current_shortstatehash, &StateEventType::RoomEncryption, "")
-				.await
-				.is_ok();
-
-			if let Some(since_shortstatehash) = since_shortstatehash {
-				// Skip if there are only timeline changes
-				if since_shortstatehash == current_shortstatehash {
-					continue;
-				}
-
-				let since_encryption = services
-					.rooms
-					.state_accessor
-					.state_get(since_shortstatehash, &StateEventType::RoomEncryption, "")
-					.await;
-
-				let since_sender_member: Option<RoomMemberEventContent> = services
-					.rooms
-					.state_accessor
-					.state_get_content(since_shortstatehash, &StateEventType::RoomMember, sender_user.as_str())
-					.ok()
-					.await;
-
-				let joined_since_last_sync =
-					since_sender_member.map_or(true, |member| member.membership != MembershipState::Join);
-
-				let new_encrypted_room = encrypted_room && since_encryption.is_err();
-
-				if encrypted_room {
-					let current_state_ids = services
-						.rooms
-						.state_accessor
-						.state_full_ids(current_shortstatehash)
-						.await?;
-
-					let since_state_ids = services
-						.rooms
-						.state_accessor
-						.state_full_ids(since_shortstatehash)
-						.await?;
-
-					for (key, id) in current_state_ids {
-						if since_state_ids.get(&key) != Some(&id) {
-							let Ok(pdu) = services.rooms.timeline.get_pdu(&id).await else {
-								error!("Pdu in state not found: {id}");
-								continue;
-							};
-							if pdu.kind == RoomMember {
-								if let Some(state_key) = &pdu.state_key {
-									let user_id = UserId::parse(state_key.clone())
-										.map_err(|_| Error::bad_database("Invalid UserId in member PDU."))?;
-
-									if user_id == *sender_user {
-										continue;
-									}
-
-									let content: RoomMemberEventContent = pdu.get_content()?;
-									match content.membership {
-										MembershipState::Join => {
-											// A new user joined an encrypted room
-											if !share_encrypted_room(&services, sender_user, &user_id, Some(room_id))
-												.await
-											{
-												device_list_changes.insert(user_id);
-											}
-										},
-										MembershipState::Leave => {
-											// Write down users that have left encrypted rooms we are in
-											left_encrypted_users.insert(user_id);
-										},
-										_ => {},
-									}
-								}
-							}
-						}
-					}
-					if joined_since_last_sync || new_encrypted_room {
-						// If the user is in a new encrypted room, give them all joined users
-						device_list_changes.extend(
-							services
-								.rooms
-								.state_cache
-								.room_members(room_id)
-								// Don't send key updates from the sender to the sender
-								.ready_filter(|user_id| sender_user != user_id)
-								// Only send keys if the sender doesn't share an encrypted room with the target
-								// already
-								.filter_map(|user_id| {
-									share_encrypted_room(&services, sender_user, user_id, Some(room_id))
-										.map(|res| res.or_some(user_id.to_owned()))
-								})
-								.collect::<Vec<_>>()
-								.await,
-						);
-					}
-				}
-			}
-			// Look for device list updates in this room
-			device_list_changes.extend(
-				services
-					.users
-					.keys_changed(room_id.as_ref(), globalsince, None)
-					.map(ToOwned::to_owned)
-					.collect::<Vec<_>>()
-					.await,
-			);
-		}
-
-		for user_id in left_encrypted_users {
-			let dont_share_encrypted_room = !share_encrypted_room(&services, sender_user, &user_id, None).await;
-
-			// If the user doesn't share an encrypted room with the target anymore, we need
-			// to tell them
-			if dont_share_encrypted_room {
-				device_list_left.insert(user_id);
-			}
-		}
-	}
-
-	let mut lists = BTreeMap::new();
-	let mut todo_rooms = BTreeMap::new(); // and required state
-
-	for (list_id, list) in &body.lists {
-		let active_rooms = match list.filters.clone().and_then(|f| f.is_invite) {
-			Some(true) => &all_invited_rooms,
-			Some(false) => &all_joined_rooms,
-			None => &all_rooms,
-		};
-
-		let active_rooms = match list.filters.clone().map(|f| f.not_room_types) {
-			Some(filter) if filter.is_empty() => active_rooms.clone(),
-			Some(value) => filter_rooms(active_rooms, State(services), &value, true).await,
-			None => active_rooms.clone(),
-		};
-
-		let active_rooms = match list.filters.clone().map(|f| f.room_types) {
-			Some(filter) if filter.is_empty() => active_rooms.clone(),
-			Some(value) => filter_rooms(&active_rooms, State(services), &value, false).await,
-			None => active_rooms,
-		};
-
-		let mut new_known_rooms = BTreeSet::new();
-
-		let ranges = list.ranges.clone();
-		lists.insert(
-			list_id.clone(),
-			sync_events::v4::SyncList {
-				ops: ranges
-					.into_iter()
-					.map(|mut r| {
-						r.0 = r.0.clamp(
-							uint!(0),
-							UInt::try_from(active_rooms.len().saturating_sub(1)).unwrap_or(UInt::MAX),
-						);
-						r.1 =
-							r.1.clamp(r.0, UInt::try_from(active_rooms.len().saturating_sub(1)).unwrap_or(UInt::MAX));
-
-						let room_ids = if !active_rooms.is_empty() {
-							active_rooms[usize_from_ruma(r.0)..=usize_from_ruma(r.1)].to_vec()
-						} else {
-							Vec::new()
-						};
-
-						new_known_rooms.extend(room_ids.iter().cloned());
-						for room_id in &room_ids {
-							let todo_room = todo_rooms
-								.entry(room_id.clone())
-								.or_insert((BTreeSet::new(), 0, u64::MAX));
-
-							let limit = list
-								.room_details
-								.timeline_limit
-								.map_or(10, u64::from)
-								.min(100);
-
-							todo_room
-								.0
-								.extend(list.room_details.required_state.iter().cloned());
-
-							todo_room.1 = todo_room.1.max(limit);
-							// 0 means unknown because it got out of date
-							todo_room.2 = todo_room.2.min(
-								known_rooms
-									.get(list_id.as_str())
-									.and_then(|k| k.get(room_id))
-									.copied()
-									.unwrap_or(0),
-							);
-						}
-						sync_events::v4::SyncOp {
-							op: SlidingOp::Sync,
-							range: Some(r),
-							index: None,
-							room_ids,
-							room_id: None,
-						}
-					})
-					.collect(),
-				count: ruma_from_usize(active_rooms.len()),
-			},
-		);
-
-		if let Some(conn_id) = &body.conn_id {
-			services.sync.update_sync_known_rooms(
-				sender_user.clone(),
-				sender_device.clone(),
-				conn_id.clone(),
-				list_id.clone(),
-				new_known_rooms,
-				globalsince,
-			);
-		}
-	}
-
-	let mut known_subscription_rooms = BTreeSet::new();
-	for (room_id, room) in &body.room_subscriptions {
-		if !services.rooms.metadata.exists(room_id).await {
-			continue;
-		}
-		let todo_room = todo_rooms
-			.entry(room_id.clone())
-			.or_insert((BTreeSet::new(), 0, u64::MAX));
-		let limit = room.timeline_limit.map_or(10, u64::from).min(100);
-		todo_room.0.extend(room.required_state.iter().cloned());
-		todo_room.1 = todo_room.1.max(limit);
-		// 0 means unknown because it got out of date
-		todo_room.2 = todo_room.2.min(
-			known_rooms
-				.get("subscriptions")
-				.and_then(|k| k.get(room_id))
-				.copied()
-				.unwrap_or(0),
-		);
-		known_subscription_rooms.insert(room_id.clone());
-	}
-
-	for r in body.unsubscribe_rooms {
-		known_subscription_rooms.remove(&r);
-		body.room_subscriptions.remove(&r);
-	}
-
-	if let Some(conn_id) = &body.conn_id {
-		services.sync.update_sync_known_rooms(
-			sender_user.clone(),
-			sender_device.clone(),
-			conn_id.clone(),
-			"subscriptions".to_owned(),
-			known_subscription_rooms,
-			globalsince,
-		);
-	}
-
-	if let Some(conn_id) = &body.conn_id {
-		services.sync.update_sync_subscriptions(
-			sender_user.clone(),
-			sender_device.clone(),
-			conn_id.clone(),
-			body.room_subscriptions,
-		);
-	}
-
-	let mut rooms = BTreeMap::new();
-	for (room_id, (required_state_request, timeline_limit, roomsince)) in &todo_rooms {
-		let roomsincecount = PduCount::Normal(*roomsince);
-
-		let mut timestamp: Option<_> = None;
-		let mut invite_state = None;
-		let (timeline_pdus, limited);
-		if all_invited_rooms.contains(room_id) {
-			// TODO: figure out a timestamp we can use for remote invites
-			invite_state = services
-				.rooms
-				.state_cache
-				.invite_state(sender_user, room_id)
-				.await
-				.ok();
-
-			(timeline_pdus, limited) = (Vec::new(), true);
-		} else {
-			(timeline_pdus, limited) =
-				match load_timeline(&services, sender_user, room_id, roomsincecount, *timeline_limit).await {
-					Ok(value) => value,
-					Err(err) => {
-						warn!("Encountered missing timeline in {}, error {}", room_id, err);
-						continue;
-					},
-				};
-		}
-
-		account_data.rooms.insert(
-			room_id.clone(),
-			services
-				.account_data
-				.changes_since(Some(room_id), sender_user, *roomsince)
-				.await?
-				.into_iter()
-				.filter_map(|e| extract_variant!(e, AnyRawAccountDataEvent::Room))
-				.collect(),
-		);
-
-		let vector: Vec<_> = services
-			.rooms
-			.read_receipt
-			.readreceipts_since(room_id, *roomsince)
-			.filter_map(|(read_user, ts, v)| async move {
-				(!services
-					.users
-					.user_is_ignored(&read_user, sender_user)
-					.await)
-					.then_some((read_user, ts, v))
-			})
-			.collect()
-			.await;
-
-		let receipt_size = vector.len();
-		receipts
-			.rooms
-			.insert(room_id.clone(), pack_receipts(Box::new(vector.into_iter())));
-
-		if roomsince != &0
-			&& timeline_pdus.is_empty()
-			&& account_data.rooms.get(room_id).is_some_and(Vec::is_empty)
-			&& receipt_size == 0
-		{
-			continue;
-		}
-
-		let prev_batch = timeline_pdus
-			.first()
-			.map_or(Ok::<_, Error>(None), |(pdu_count, _)| {
-				Ok(Some(match pdu_count {
-					PduCount::Backfilled(_) => {
-						error!("timeline in backfill state?!");
-						"0".to_owned()
-					},
-					PduCount::Normal(c) => c.to_string(),
-				}))
-			})?
-			.or_else(|| {
-				if roomsince != &0 {
-					Some(roomsince.to_string())
-				} else {
-					None
-				}
-			});
-
-		let room_events: Vec<_> = timeline_pdus
-			.iter()
-			.stream()
-			.filter_map(|(_, pdu)| async move {
-				// list of safe and common non-state events to ignore
-				if matches!(
-					&pdu.kind,
-					RoomMessage
-						| Sticker | CallInvite
-						| CallNotify | RoomEncrypted
-						| Image | File | Audio
-						| Voice | Video | UnstablePollStart
-						| PollStart | KeyVerificationStart
-						| Reaction | Emote | Location
-				) && services
-					.users
-					.user_is_ignored(&pdu.sender, sender_user)
-					.await
-				{
-					return None;
-				}
-
-				Some(pdu.to_sync_room_event())
-			})
-			.collect()
-			.await;
-
-		for (_, pdu) in timeline_pdus {
-			let ts = MilliSecondsSinceUnixEpoch(pdu.origin_server_ts);
-			if DEFAULT_BUMP_TYPES.contains(pdu.event_type()) && !timestamp.is_some_and(|time| time > ts) {
-				timestamp = Some(ts);
-			}
-		}
-
-		let required_state = required_state_request
-			.iter()
-			.stream()
-			.filter_map(|state| async move {
-				services
-					.rooms
-					.state_accessor
-					.room_state_get(room_id, &state.0, &state.1)
-					.await
-					.map(|s| s.to_sync_state_event())
-					.ok()
-			})
-			.collect()
-			.await;
-
-		// Heroes
-		let heroes: Vec<_> = services
-			.rooms
-			.state_cache
-			.room_members(room_id)
-			.ready_filter(|member| member != sender_user)
-			.filter_map(|user_id| {
-				services
-					.rooms
-					.state_accessor
-					.get_member(room_id, user_id)
-					.map_ok(|memberevent| SlidingSyncRoomHero {
-						user_id: user_id.into(),
-						name: memberevent.displayname,
-						avatar: memberevent.avatar_url,
-					})
-					.ok()
-			})
-			.take(5)
-			.collect()
-			.await;
-
-		let name = match heroes.len().cmp(&(1_usize)) {
-			Ordering::Greater => {
-				let firsts = heroes[1..]
-					.iter()
-					.map(|h| h.name.clone().unwrap_or_else(|| h.user_id.to_string()))
-					.collect::<Vec<_>>()
-					.join(", ");
-
-				let last = heroes[0]
-					.name
-					.clone()
-					.unwrap_or_else(|| heroes[0].user_id.to_string());
-
-				Some(format!("{firsts} and {last}"))
-			},
-			Ordering::Equal => Some(
-				heroes[0]
-					.name
-					.clone()
-					.unwrap_or_else(|| heroes[0].user_id.to_string()),
-			),
-			Ordering::Less => None,
-		};
-
-		let heroes_avatar = if heroes.len() == 1 {
-			heroes[0].avatar.clone()
-		} else {
-			None
-		};
-
-		rooms.insert(
-			room_id.clone(),
-			sync_events::v4::SlidingSyncRoom {
-				name: services
-					.rooms
-					.state_accessor
-					.get_name(room_id)
-					.await
-					.ok()
-					.or(name),
-				avatar: if let Some(heroes_avatar) = heroes_avatar {
-					ruma::JsOption::Some(heroes_avatar)
-				} else {
-					match services.rooms.state_accessor.get_avatar(room_id).await {
-						ruma::JsOption::Some(avatar) => ruma::JsOption::from_option(avatar.url),
-						ruma::JsOption::Null => ruma::JsOption::Null,
-						ruma::JsOption::Undefined => ruma::JsOption::Undefined,
-					}
-				},
-				initial: Some(roomsince == &0),
-				is_dm: None,
-				invite_state,
-				unread_notifications: UnreadNotificationsCount {
-					highlight_count: Some(
-						services
-							.rooms
-							.user
-							.highlight_count(sender_user, room_id)
-							.await
-							.try_into()
-							.expect("notification count can't go that high"),
-					),
-					notification_count: Some(
-						services
-							.rooms
-							.user
-							.notification_count(sender_user, room_id)
-							.await
-							.try_into()
-							.expect("notification count can't go that high"),
-					),
-				},
-				timeline: room_events,
-				required_state,
-				prev_batch,
-				limited,
-				joined_count: Some(
-					services
-						.rooms
-						.state_cache
-						.room_joined_count(room_id)
-						.await
-						.unwrap_or(0)
-						.try_into()
-						.unwrap_or_else(|_| uint!(0)),
-				),
-				invited_count: Some(
-					services
-						.rooms
-						.state_cache
-						.room_invited_count(room_id)
-						.await
-						.unwrap_or(0)
-						.try_into()
-						.unwrap_or_else(|_| uint!(0)),
-				),
-				num_live: None, // Count events in timeline greater than global sync counter
-				timestamp,
-				heroes: Some(heroes),
-			},
-		);
-	}
-
-	if rooms
-		.iter()
-		.all(|(_, r)| r.timeline.is_empty() && r.required_state.is_empty())
-	{
-		// Hang a few seconds so requests are not spammed
-		// Stop hanging if new info arrives
-		let default = Duration::from_secs(30);
-		let duration = cmp::min(body.timeout.unwrap_or(default), default);
-		_ = tokio::time::timeout(duration, watcher).await;
-	}
-
-	Ok(sync_events::v4::Response {
-		initial: globalsince == 0,
-		txn_id: body.txn_id.clone(),
-		pos: next_batch.to_string(),
-		lists,
-		rooms,
-		extensions: sync_events::v4::Extensions {
-			to_device: if body.extensions.to_device.enabled.unwrap_or(false) {
-				Some(sync_events::v4::ToDevice {
-					events: services
-						.users
-						.get_to_device_events(sender_user, &sender_device)
-						.collect()
-						.await,
-					next_batch: next_batch.to_string(),
-				})
-			} else {
-				None
-			},
-			e2ee: sync_events::v4::E2EE {
-				device_lists: DeviceLists {
-					changed: device_list_changes.into_iter().collect(),
-					left: device_list_left.into_iter().collect(),
-				},
-				device_one_time_keys_count: services
-					.users
-					.count_one_time_keys(sender_user, &sender_device)
-					.await,
-				// Fallback keys are not yet supported
-				device_unused_fallback_key_types: None,
-			},
-			account_data,
-			receipts,
-			typing: sync_events::v4::Typing {
-				rooms: BTreeMap::new(),
-			},
-		},
-		delta_token: None,
-	})
-}
-
-async fn filter_rooms(
-	rooms: &[OwnedRoomId], State(services): State<crate::State>, filter: &[RoomTypeFilter], negate: bool,
-) -> Vec<OwnedRoomId> {
-	rooms
-		.iter()
-		.stream()
-		.filter_map(|r| async move {
-			let room_type = services.rooms.state_accessor.get_room_type(r).await;
-
-			if room_type.as_ref().is_err_and(|e| !e.is_not_found()) {
-				return None;
-			}
-
-			let room_type_filter = RoomTypeFilter::from(room_type.ok());
-
-			let include = if negate {
-				!filter.contains(&room_type_filter)
-			} else {
-				filter.is_empty() || filter.contains(&room_type_filter)
-			};
-
-			include.then_some(r.to_owned())
-		})
-		.collect()
-		.await
-}
diff --git a/src/api/client/sync/v4.rs b/src/api/client/sync/v4.rs
new file mode 100644
index 00000000..2adb3b71
--- /dev/null
+++ b/src/api/client/sync/v4.rs
@@ -0,0 +1,784 @@
+use std::{
+	cmp::{self, Ordering},
+	collections::{BTreeMap, BTreeSet, HashSet},
+	time::Duration,
+};
+
+use axum::extract::State;
+use conduit::{
+	debug, error, extract_variant,
+	utils::{
+		math::{ruma_from_usize, usize_from_ruma},
+		BoolExt, IterStream, ReadyExt, TryFutureExtExt,
+	},
+	warn, Error, PduCount, Result,
+};
+use futures::{FutureExt, StreamExt, TryFutureExt};
+use ruma::{
+	api::client::{
+		error::ErrorKind,
+		sync::sync_events::{
+			self,
+			v4::{SlidingOp, SlidingSyncRoomHero},
+			DeviceLists, UnreadNotificationsCount,
+		},
+	},
+	directory::RoomTypeFilter,
+	events::{
+		room::member::{MembershipState, RoomMemberEventContent},
+		AnyRawAccountDataEvent, StateEventType,
+		TimelineEventType::{self, *},
+	},
+	state_res::Event,
+	uint, MilliSecondsSinceUnixEpoch, OwnedRoomId, UInt, UserId,
+};
+use service::{rooms::read_receipt::pack_receipts, Services};
+
+use super::{load_timeline, share_encrypted_room};
+use crate::Ruma;
+
+const SINGLE_CONNECTION_SYNC: &str = "single_connection_sync";
+const DEFAULT_BUMP_TYPES: &[TimelineEventType; 6] =
+	&[RoomMessage, RoomEncrypted, Sticker, CallInvite, PollStart, Beacon];
+
+/// POST `/_matrix/client/unstable/org.matrix.msc3575/sync`
+///
+/// Sliding Sync endpoint (future endpoint: `/_matrix/client/v4/sync`)
+pub(crate) async fn sync_events_v4_route(
+	State(services): State<crate::State>, body: Ruma<sync_events::v4::Request>,
+) -> Result<sync_events::v4::Response> {
+	let sender_user = body.sender_user.as_ref().expect("user is authenticated");
+	let sender_device = body.sender_device.expect("user is authenticated");
+	let mut body = body.body;
+	// Setup watchers, so if there's no response, we can wait for them
+	let watcher = services.globals.watch(sender_user, &sender_device);
+
+	let next_batch = services.globals.next_count()?;
+
+	let conn_id = body
+		.conn_id
+		.clone()
+		.unwrap_or_else(|| SINGLE_CONNECTION_SYNC.to_owned());
+
+	let globalsince = body
+		.pos
+		.as_ref()
+		.and_then(|string| string.parse().ok())
+		.unwrap_or(0);
+
+	if globalsince != 0
+		&& !services
+			.sync
+			.remembered(sender_user.clone(), sender_device.clone(), conn_id.clone())
+	{
+		debug!("Restarting sync stream because it was gone from the database");
+		return Err(Error::Request(
+			ErrorKind::UnknownPos,
+			"Connection data lost since last time".into(),
+			http::StatusCode::BAD_REQUEST,
+		));
+	}
+
+	if globalsince == 0 {
+		services
+			.sync
+			.forget_sync_request_connection(sender_user.clone(), sender_device.clone(), conn_id.clone());
+	}
+
+	// Get sticky parameters from cache
+	let known_rooms =
+		services
+			.sync
+			.update_sync_request_with_cache(sender_user.clone(), sender_device.clone(), &mut body);
+
+	let all_joined_rooms: Vec<_> = services
+		.rooms
+		.state_cache
+		.rooms_joined(sender_user)
+		.map(ToOwned::to_owned)
+		.collect()
+		.await;
+
+	let all_invited_rooms: Vec<_> = services
+		.rooms
+		.state_cache
+		.rooms_invited(sender_user)
+		.map(|r| r.0)
+		.collect()
+		.await;
+
+	let all_rooms = all_joined_rooms
+		.iter()
+		.chain(all_invited_rooms.iter())
+		.map(Clone::clone)
+		.collect();
+
+	if body.extensions.to_device.enabled.unwrap_or(false) {
+		services
+			.users
+			.remove_to_device_events(sender_user, &sender_device, globalsince)
+			.await;
+	}
+
+	let mut left_encrypted_users = HashSet::new(); // Users that have left any encrypted rooms the sender was in
+	let mut device_list_changes = HashSet::new();
+	let mut device_list_left = HashSet::new();
+
+	let mut receipts = sync_events::v4::Receipts {
+		rooms: BTreeMap::new(),
+	};
+
+	let mut account_data = sync_events::v4::AccountData {
+		global: Vec::new(),
+		rooms: BTreeMap::new(),
+	};
+	if body.extensions.account_data.enabled.unwrap_or(false) {
+		account_data.global = services
+			.account_data
+			.changes_since(None, sender_user, globalsince)
+			.await?
+			.into_iter()
+			.filter_map(|e| extract_variant!(e, AnyRawAccountDataEvent::Global))
+			.collect();
+
+		if let Some(rooms) = body.extensions.account_data.rooms {
+			for room in rooms {
+				account_data.rooms.insert(
+					room.clone(),
+					services
+						.account_data
+						.changes_since(Some(&room), sender_user, globalsince)
+						.await?
+						.into_iter()
+						.filter_map(|e| extract_variant!(e, AnyRawAccountDataEvent::Room))
+						.collect(),
+				);
+			}
+		}
+	}
+
+	if body.extensions.e2ee.enabled.unwrap_or(false) {
+		// Look for device list updates of this account
+		device_list_changes.extend(
+			services
+				.users
+				.keys_changed(sender_user.as_ref(), globalsince, None)
+				.map(ToOwned::to_owned)
+				.collect::<Vec<_>>()
+				.await,
+		);
+
+		for room_id in &all_joined_rooms {
+			let Ok(current_shortstatehash) = services.rooms.state.get_room_shortstatehash(room_id).await else {
+				error!("Room {room_id} has no state");
+				continue;
+			};
+
+			let since_shortstatehash = services
+				.rooms
+				.user
+				.get_token_shortstatehash(room_id, globalsince)
+				.await
+				.ok();
+
+			let encrypted_room = services
+				.rooms
+				.state_accessor
+				.state_get(current_shortstatehash, &StateEventType::RoomEncryption, "")
+				.await
+				.is_ok();
+
+			if let Some(since_shortstatehash) = since_shortstatehash {
+				// Skip if there are only timeline changes
+				if since_shortstatehash == current_shortstatehash {
+					continue;
+				}
+
+				let since_encryption = services
+					.rooms
+					.state_accessor
+					.state_get(since_shortstatehash, &StateEventType::RoomEncryption, "")
+					.await;
+
+				let since_sender_member: Option<RoomMemberEventContent> = services
+					.rooms
+					.state_accessor
+					.state_get_content(since_shortstatehash, &StateEventType::RoomMember, sender_user.as_str())
+					.ok()
+					.await;
+
+				let joined_since_last_sync =
+					since_sender_member.map_or(true, |member| member.membership != MembershipState::Join);
+
+				let new_encrypted_room = encrypted_room && since_encryption.is_err();
+
+				if encrypted_room {
+					let current_state_ids = services
+						.rooms
+						.state_accessor
+						.state_full_ids(current_shortstatehash)
+						.await?;
+
+					let since_state_ids = services
+						.rooms
+						.state_accessor
+						.state_full_ids(since_shortstatehash)
+						.await?;
+
+					for (key, id) in current_state_ids {
+						if since_state_ids.get(&key) != Some(&id) {
+							let Ok(pdu) = services.rooms.timeline.get_pdu(&id).await else {
+								error!("Pdu in state not found: {id}");
+								continue;
+							};
+							if pdu.kind == RoomMember {
+								if let Some(state_key) = &pdu.state_key {
+									let user_id = UserId::parse(state_key.clone())
+										.map_err(|_| Error::bad_database("Invalid UserId in member PDU."))?;
+
+									if user_id == *sender_user {
+										continue;
+									}
+
+									let content: RoomMemberEventContent = pdu.get_content()?;
+									match content.membership {
+										MembershipState::Join => {
+											// A new user joined an encrypted room
+											if !share_encrypted_room(&services, sender_user, &user_id, Some(room_id))
+												.await
+											{
+												device_list_changes.insert(user_id);
+											}
+										},
+										MembershipState::Leave => {
+											// Write down users that have left encrypted rooms we are in
+											left_encrypted_users.insert(user_id);
+										},
+										_ => {},
+									}
+								}
+							}
+						}
+					}
+					if joined_since_last_sync || new_encrypted_room {
+						// If the user is in a new encrypted room, give them all joined users
+						device_list_changes.extend(
+							services
+								.rooms
+								.state_cache
+								.room_members(room_id)
+								// Don't send key updates from the sender to the sender
+								.ready_filter(|user_id| sender_user != user_id)
+								// Only send keys if the sender doesn't share an encrypted room with the target
+								// already
+								.filter_map(|user_id| {
+									share_encrypted_room(&services, sender_user, user_id, Some(room_id))
+										.map(|res| res.or_some(user_id.to_owned()))
+								})
+								.collect::<Vec<_>>()
+								.await,
+						);
+					}
+				}
+			}
+			// Look for device list updates in this room
+			device_list_changes.extend(
+				services
+					.users
+					.keys_changed(room_id.as_ref(), globalsince, None)
+					.map(ToOwned::to_owned)
+					.collect::<Vec<_>>()
+					.await,
+			);
+		}
+
+		for user_id in left_encrypted_users {
+			let dont_share_encrypted_room = !share_encrypted_room(&services, sender_user, &user_id, None).await;
+
+			// If the user doesn't share an encrypted room with the target anymore, we need
+			// to tell them
+			if dont_share_encrypted_room {
+				device_list_left.insert(user_id);
+			}
+		}
+	}
+
+	let mut lists = BTreeMap::new();
+	let mut todo_rooms = BTreeMap::new(); // and required state
+
+	for (list_id, list) in &body.lists {
+		let active_rooms = match list.filters.clone().and_then(|f| f.is_invite) {
+			Some(true) => &all_invited_rooms,
+			Some(false) => &all_joined_rooms,
+			None => &all_rooms,
+		};
+
+		let active_rooms = match list.filters.clone().map(|f| f.not_room_types) {
+			Some(filter) if filter.is_empty() => active_rooms.clone(),
+			Some(value) => filter_rooms(&services, active_rooms, &value, true).await,
+			None => active_rooms.clone(),
+		};
+
+		let active_rooms = match list.filters.clone().map(|f| f.room_types) {
+			Some(filter) if filter.is_empty() => active_rooms.clone(),
+			Some(value) => filter_rooms(&services, &active_rooms, &value, false).await,
+			None => active_rooms,
+		};
+
+		let mut new_known_rooms = BTreeSet::new();
+
+		let ranges = list.ranges.clone();
+		lists.insert(
+			list_id.clone(),
+			sync_events::v4::SyncList {
+				ops: ranges
+					.into_iter()
+					.map(|mut r| {
+						r.0 = r.0.clamp(
+							uint!(0),
+							UInt::try_from(active_rooms.len().saturating_sub(1)).unwrap_or(UInt::MAX),
+						);
+						r.1 =
+							r.1.clamp(r.0, UInt::try_from(active_rooms.len().saturating_sub(1)).unwrap_or(UInt::MAX));
+
+						let room_ids = if !active_rooms.is_empty() {
+							active_rooms[usize_from_ruma(r.0)..=usize_from_ruma(r.1)].to_vec()
+						} else {
+							Vec::new()
+						};
+
+						new_known_rooms.extend(room_ids.iter().cloned());
+						for room_id in &room_ids {
+							let todo_room = todo_rooms
+								.entry(room_id.clone())
+								.or_insert((BTreeSet::new(), 0, u64::MAX));
+
+							let limit = list
+								.room_details
+								.timeline_limit
+								.map_or(10, u64::from)
+								.min(100);
+
+							todo_room
+								.0
+								.extend(list.room_details.required_state.iter().cloned());
+
+							todo_room.1 = todo_room.1.max(limit);
+							// 0 means unknown because it got out of date
+							todo_room.2 = todo_room.2.min(
+								known_rooms
+									.get(list_id.as_str())
+									.and_then(|k| k.get(room_id))
+									.copied()
+									.unwrap_or(0),
+							);
+						}
+						sync_events::v4::SyncOp {
+							op: SlidingOp::Sync,
+							range: Some(r),
+							index: None,
+							room_ids,
+							room_id: None,
+						}
+					})
+					.collect(),
+				count: ruma_from_usize(active_rooms.len()),
+			},
+		);
+
+		if let Some(conn_id) = &body.conn_id {
+			services.sync.update_sync_known_rooms(
+				sender_user.clone(),
+				sender_device.clone(),
+				conn_id.clone(),
+				list_id.clone(),
+				new_known_rooms,
+				globalsince,
+			);
+		}
+	}
+
+	let mut known_subscription_rooms = BTreeSet::new();
+	for (room_id, room) in &body.room_subscriptions {
+		if !services.rooms.metadata.exists(room_id).await {
+			continue;
+		}
+		let todo_room = todo_rooms
+			.entry(room_id.clone())
+			.or_insert((BTreeSet::new(), 0, u64::MAX));
+		let limit = room.timeline_limit.map_or(10, u64::from).min(100);
+		todo_room.0.extend(room.required_state.iter().cloned());
+		todo_room.1 = todo_room.1.max(limit);
+		// 0 means unknown because it got out of date
+		todo_room.2 = todo_room.2.min(
+			known_rooms
+				.get("subscriptions")
+				.and_then(|k| k.get(room_id))
+				.copied()
+				.unwrap_or(0),
+		);
+		known_subscription_rooms.insert(room_id.clone());
+	}
+
+	for r in body.unsubscribe_rooms {
+		known_subscription_rooms.remove(&r);
+		body.room_subscriptions.remove(&r);
+	}
+
+	if let Some(conn_id) = &body.conn_id {
+		services.sync.update_sync_known_rooms(
+			sender_user.clone(),
+			sender_device.clone(),
+			conn_id.clone(),
+			"subscriptions".to_owned(),
+			known_subscription_rooms,
+			globalsince,
+		);
+	}
+
+	if let Some(conn_id) = &body.conn_id {
+		services.sync.update_sync_subscriptions(
+			sender_user.clone(),
+			sender_device.clone(),
+			conn_id.clone(),
+			body.room_subscriptions,
+		);
+	}
+
+	let mut rooms = BTreeMap::new();
+	for (room_id, (required_state_request, timeline_limit, roomsince)) in &todo_rooms {
+		let roomsincecount = PduCount::Normal(*roomsince);
+
+		let mut timestamp: Option<_> = None;
+		let mut invite_state = None;
+		let (timeline_pdus, limited);
+		if all_invited_rooms.contains(room_id) {
+			// TODO: figure out a timestamp we can use for remote invites
+			invite_state = services
+				.rooms
+				.state_cache
+				.invite_state(sender_user, room_id)
+				.await
+				.ok();
+
+			(timeline_pdus, limited) = (Vec::new(), true);
+		} else {
+			(timeline_pdus, limited) =
+				match load_timeline(&services, sender_user, room_id, roomsincecount, *timeline_limit).await {
+					Ok(value) => value,
+					Err(err) => {
+						warn!("Encountered missing timeline in {}, error {}", room_id, err);
+						continue;
+					},
+				};
+		}
+
+		account_data.rooms.insert(
+			room_id.clone(),
+			services
+				.account_data
+				.changes_since(Some(room_id), sender_user, *roomsince)
+				.await?
+				.into_iter()
+				.filter_map(|e| extract_variant!(e, AnyRawAccountDataEvent::Room))
+				.collect(),
+		);
+
+		let vector: Vec<_> = services
+			.rooms
+			.read_receipt
+			.readreceipts_since(room_id, *roomsince)
+			.filter_map(|(read_user, ts, v)| async move {
+				(!services
+					.users
+					.user_is_ignored(&read_user, sender_user)
+					.await)
+					.then_some((read_user, ts, v))
+			})
+			.collect()
+			.await;
+
+		let receipt_size = vector.len();
+		receipts
+			.rooms
+			.insert(room_id.clone(), pack_receipts(Box::new(vector.into_iter())));
+
+		if roomsince != &0
+			&& timeline_pdus.is_empty()
+			&& account_data.rooms.get(room_id).is_some_and(Vec::is_empty)
+			&& receipt_size == 0
+		{
+			continue;
+		}
+
+		let prev_batch = timeline_pdus
+			.first()
+			.map_or(Ok::<_, Error>(None), |(pdu_count, _)| {
+				Ok(Some(match pdu_count {
+					PduCount::Backfilled(_) => {
+						error!("timeline in backfill state?!");
+						"0".to_owned()
+					},
+					PduCount::Normal(c) => c.to_string(),
+				}))
+			})?
+			.or_else(|| {
+				if roomsince != &0 {
+					Some(roomsince.to_string())
+				} else {
+					None
+				}
+			});
+
+		let room_events: Vec<_> = timeline_pdus
+			.iter()
+			.stream()
+			.filter_map(|(_, pdu)| async move {
+				// list of safe and common non-state events to ignore
+				if matches!(
+					&pdu.kind,
+					RoomMessage
+						| Sticker | CallInvite
+						| CallNotify | RoomEncrypted
+						| Image | File | Audio
+						| Voice | Video | UnstablePollStart
+						| PollStart | KeyVerificationStart
+						| Reaction | Emote | Location
+				) && services
+					.users
+					.user_is_ignored(&pdu.sender, sender_user)
+					.await
+				{
+					return None;
+				}
+
+				Some(pdu.to_sync_room_event())
+			})
+			.collect()
+			.await;
+
+		for (_, pdu) in timeline_pdus {
+			let ts = MilliSecondsSinceUnixEpoch(pdu.origin_server_ts);
+			if DEFAULT_BUMP_TYPES.contains(pdu.event_type()) && !timestamp.is_some_and(|time| time > ts) {
+				timestamp = Some(ts);
+			}
+		}
+
+		let required_state = required_state_request
+			.iter()
+			.stream()
+			.filter_map(|state| async move {
+				services
+					.rooms
+					.state_accessor
+					.room_state_get(room_id, &state.0, &state.1)
+					.await
+					.map(|s| s.to_sync_state_event())
+					.ok()
+			})
+			.collect()
+			.await;
+
+		// Heroes
+		let heroes: Vec<_> = services
+			.rooms
+			.state_cache
+			.room_members(room_id)
+			.ready_filter(|member| member != sender_user)
+			.filter_map(|user_id| {
+				services
+					.rooms
+					.state_accessor
+					.get_member(room_id, user_id)
+					.map_ok(|memberevent| SlidingSyncRoomHero {
+						user_id: user_id.into(),
+						name: memberevent.displayname,
+						avatar: memberevent.avatar_url,
+					})
+					.ok()
+			})
+			.take(5)
+			.collect()
+			.await;
+
+		let name = match heroes.len().cmp(&(1_usize)) {
+			Ordering::Greater => {
+				let firsts = heroes[1..]
+					.iter()
+					.map(|h| h.name.clone().unwrap_or_else(|| h.user_id.to_string()))
+					.collect::<Vec<_>>()
+					.join(", ");
+
+				let last = heroes[0]
+					.name
+					.clone()
+					.unwrap_or_else(|| heroes[0].user_id.to_string());
+
+				Some(format!("{firsts} and {last}"))
+			},
+			Ordering::Equal => Some(
+				heroes[0]
+					.name
+					.clone()
+					.unwrap_or_else(|| heroes[0].user_id.to_string()),
+			),
+			Ordering::Less => None,
+		};
+
+		let heroes_avatar = if heroes.len() == 1 {
+			heroes[0].avatar.clone()
+		} else {
+			None
+		};
+
+		rooms.insert(
+			room_id.clone(),
+			sync_events::v4::SlidingSyncRoom {
+				name: services
+					.rooms
+					.state_accessor
+					.get_name(room_id)
+					.await
+					.ok()
+					.or(name),
+				avatar: if let Some(heroes_avatar) = heroes_avatar {
+					ruma::JsOption::Some(heroes_avatar)
+				} else {
+					match services.rooms.state_accessor.get_avatar(room_id).await {
+						ruma::JsOption::Some(avatar) => ruma::JsOption::from_option(avatar.url),
+						ruma::JsOption::Null => ruma::JsOption::Null,
+						ruma::JsOption::Undefined => ruma::JsOption::Undefined,
+					}
+				},
+				initial: Some(roomsince == &0),
+				is_dm: None,
+				invite_state,
+				unread_notifications: UnreadNotificationsCount {
+					highlight_count: Some(
+						services
+							.rooms
+							.user
+							.highlight_count(sender_user, room_id)
+							.await
+							.try_into()
+							.expect("notification count can't go that high"),
+					),
+					notification_count: Some(
+						services
+							.rooms
+							.user
+							.notification_count(sender_user, room_id)
+							.await
+							.try_into()
+							.expect("notification count can't go that high"),
+					),
+				},
+				timeline: room_events,
+				required_state,
+				prev_batch,
+				limited,
+				joined_count: Some(
+					services
+						.rooms
+						.state_cache
+						.room_joined_count(room_id)
+						.await
+						.unwrap_or(0)
+						.try_into()
+						.unwrap_or_else(|_| uint!(0)),
+				),
+				invited_count: Some(
+					services
+						.rooms
+						.state_cache
+						.room_invited_count(room_id)
+						.await
+						.unwrap_or(0)
+						.try_into()
+						.unwrap_or_else(|_| uint!(0)),
+				),
+				num_live: None, // Count events in timeline greater than global sync counter
+				timestamp,
+				heroes: Some(heroes),
+			},
+		);
+	}
+
+	if rooms
+		.iter()
+		.all(|(_, r)| r.timeline.is_empty() && r.required_state.is_empty())
+	{
+		// Hang a few seconds so requests are not spammed
+		// Stop hanging if new info arrives
+		let default = Duration::from_secs(30);
+		let duration = cmp::min(body.timeout.unwrap_or(default), default);
+		_ = tokio::time::timeout(duration, watcher).await;
+	}
+
+	Ok(sync_events::v4::Response {
+		initial: globalsince == 0,
+		txn_id: body.txn_id.clone(),
+		pos: next_batch.to_string(),
+		lists,
+		rooms,
+		extensions: sync_events::v4::Extensions {
+			to_device: if body.extensions.to_device.enabled.unwrap_or(false) {
+				Some(sync_events::v4::ToDevice {
+					events: services
+						.users
+						.get_to_device_events(sender_user, &sender_device)
+						.collect()
+						.await,
+					next_batch: next_batch.to_string(),
+				})
+			} else {
+				None
+			},
+			e2ee: sync_events::v4::E2EE {
+				device_lists: DeviceLists {
+					changed: device_list_changes.into_iter().collect(),
+					left: device_list_left.into_iter().collect(),
+				},
+				device_one_time_keys_count: services
+					.users
+					.count_one_time_keys(sender_user, &sender_device)
+					.await,
+				// Fallback keys are not yet supported
+				device_unused_fallback_key_types: None,
+			},
+			account_data,
+			receipts,
+			typing: sync_events::v4::Typing {
+				rooms: BTreeMap::new(),
+			},
+		},
+		delta_token: None,
+	})
+}
+
+async fn filter_rooms(
+	services: &Services, rooms: &[OwnedRoomId], filter: &[RoomTypeFilter], negate: bool,
+) -> Vec<OwnedRoomId> {
+	rooms
+		.iter()
+		.stream()
+		.filter_map(|r| async move {
+			let room_type = services.rooms.state_accessor.get_room_type(r).await;
+
+			if room_type.as_ref().is_err_and(|e| !e.is_not_found()) {
+				return None;
+			}
+
+			let room_type_filter = RoomTypeFilter::from(room_type.ok());
+
+			let include = if negate {
+				!filter.contains(&room_type_filter)
+			} else {
+				filter.is_empty() || filter.contains(&room_type_filter)
+			};
+
+			include.then_some(r.to_owned())
+		})
+		.collect()
+		.await
+}
diff --git a/src/core/utils/mod.rs b/src/core/utils/mod.rs
index 3adecc6c..96a98537 100644
--- a/src/core/utils/mod.rs
+++ b/src/core/utils/mod.rs
@@ -40,6 +40,16 @@ pub use self::{
 #[inline]
 pub fn exchange<T>(state: &mut T, source: T) -> T { std::mem::replace(state, source) }
 
+#[macro_export]
+macro_rules! extract_variant {
+	($e:expr, $variant:path) => {
+		match $e {
+			$variant(value) => Some(value),
+			_ => None,
+		}
+	};
+}
+
 #[macro_export]
 macro_rules! at {
 	($idx:tt) => {