diff --git a/Cargo.toml b/Cargo.toml
index fd2da7b1..22e57bb5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -78,6 +78,7 @@ string_to_string = "warn"
 struct_excessive_bools = "warn"
 suspicious_xor_used_as_pow = "warn"
 tests_outside_test_module = "warn"
+too_many_lines = "warn"
 try_err = "warn"
 undocumented_unsafe_blocks = "warn"
 unnecessary_safety_comment = "warn"
diff --git a/src/api/client_server/account.rs b/src/api/client_server/account.rs
index 54b735b3..6d254a9c 100644
--- a/src/api/client_server/account.rs
+++ b/src/api/client_server/account.rs
@@ -74,6 +74,7 @@ pub(crate) async fn get_register_available_route(
 /// - If type is not guest and no username is given: Always fails after UIAA check
 /// - Creates a new account and populates it with default account data
 /// - If `inhibit_login` is false: Creates a device and returns `device_id` and `access_token`
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn register_route(
     body: Ruma<register::v3::Request>,
 ) -> Result<register::v3::Response> {
diff --git a/src/api/client_server/context.rs b/src/api/client_server/context.rs
index 14f5eb0d..a063a2ec 100644
--- a/src/api/client_server/context.rs
+++ b/src/api/client_server/context.rs
@@ -13,6 +13,7 @@ use tracing::error;
 ///
 /// - Only works if the user is joined (TODO: always allow, but only show events if the user was
 /// joined, depending on `history_visibility`)
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn get_context_route(
     body: Ruma<get_context::v3::Request>,
 ) -> Result<get_context::v3::Response> {
diff --git a/src/api/client_server/directory.rs b/src/api/client_server/directory.rs
index 4d926442..f4141fa9 100644
--- a/src/api/client_server/directory.rs
+++ b/src/api/client_server/directory.rs
@@ -123,6 +123,7 @@ pub(crate) async fn get_room_visibility_route(
     })
 }
 
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn get_public_rooms_filtered_helper(
     server: Option<&ServerName>,
     limit: Option<UInt>,
diff --git a/src/api/client_server/keys.rs b/src/api/client_server/keys.rs
index 4c104a6b..8a9191d1 100644
--- a/src/api/client_server/keys.rs
+++ b/src/api/client_server/keys.rs
@@ -256,6 +256,7 @@ pub(crate) async fn get_key_changes_route(
     })
 }
 
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn get_keys_helper<F: Fn(&UserId) -> bool>(
     sender_user: Option<&UserId>,
     device_keys_input: &BTreeMap<OwnedUserId, Vec<OwnedDeviceId>>,
diff --git a/src/api/client_server/membership.rs b/src/api/client_server/membership.rs
index 21332ed9..84b92f4f 100644
--- a/src/api/client_server/membership.rs
+++ b/src/api/client_server/membership.rs
@@ -518,6 +518,7 @@ pub(crate) async fn joined_members_route(
     Ok(joined_members::v3::Response { joined })
 }
 
+#[allow(clippy::too_many_lines)]
 async fn join_room_by_id_helper(
     sender_user: Option<&UserId>,
     room_id: &RoomId,
@@ -1200,6 +1201,7 @@ async fn validate_and_add_event_id(
     Ok((event_id, value))
 }
 
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn invite_helper(
     sender_user: &UserId,
     user_id: &UserId,
diff --git a/src/api/client_server/message.rs b/src/api/client_server/message.rs
index db8c8bf8..76b367c8 100644
--- a/src/api/client_server/message.rs
+++ b/src/api/client_server/message.rs
@@ -112,6 +112,7 @@ pub(crate) async fn send_message_event_route(
 ///
 /// - Only works if the user is joined (TODO: always allow, but only show events where the user was
 /// joined, depending on `history_visibility`)
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn get_message_events_route(
     body: Ruma<get_message_events::v3::Request>,
 ) -> Result<get_message_events::v3::Response> {
diff --git a/src/api/client_server/room.rs b/src/api/client_server/room.rs
index 8167ed25..1b266e25 100644
--- a/src/api/client_server/room.rs
+++ b/src/api/client_server/room.rs
@@ -45,6 +45,7 @@ use tracing::{info, warn};
 /// - Send events listed in initial state
 /// - Send events implied by `name` and `topic`
 /// - Send invite events
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn create_room_route(
     body: Ruma<create_room::v3::Request>,
 ) -> Result<create_room::v3::Response> {
@@ -580,6 +581,7 @@ pub(crate) async fn get_room_aliases_route(
 /// - Transfers some state events
 /// - Moves local aliases
 /// - Modifies old room power levels to prevent users from speaking
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn upgrade_room_route(
     body: Ruma<upgrade_room::v3::Request>,
 ) -> Result<upgrade_room::v3::Response> {
diff --git a/src/api/client_server/search.rs b/src/api/client_server/search.rs
index 3743b877..9d69d3b8 100644
--- a/src/api/client_server/search.rs
+++ b/src/api/client_server/search.rs
@@ -17,6 +17,7 @@ use std::collections::BTreeMap;
 /// Searches rooms for messages.
 ///
 /// - Only works if the user is currently joined to the room (TODO: Respect history visibility)
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn search_events_route(
     body: Ruma<search_events::v3::Request>,
 ) -> Result<search_events::v3::Response> {
diff --git a/src/api/client_server/session.rs b/src/api/client_server/session.rs
index 9d1cc552..7a58a992 100644
--- a/src/api/client_server/session.rs
+++ b/src/api/client_server/session.rs
@@ -47,6 +47,7 @@ pub(crate) async fn get_login_types_route(
 ///
 /// Note: You can use [`GET /_matrix/client/r0/login`](fn.get_supported_versions_route.html) to see
 /// supported login types.
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn login_route(body: Ruma<login::v3::Request>) -> Result<login::v3::Response> {
     // To allow deprecated login methods
     #![allow(deprecated)]
diff --git a/src/api/client_server/sync.rs b/src/api/client_server/sync.rs
index b5799bf5..7655c66d 100644
--- a/src/api/client_server/sync.rs
+++ b/src/api/client_server/sync.rs
@@ -168,6 +168,7 @@ async fn sync_helper_wrapper(
         .expect("receiver should not be dropped");
 }
 
+#[allow(clippy::too_many_lines)]
 async fn sync_helper(
     sender_user: OwnedUserId,
     sender_device: OwnedDeviceId,
@@ -546,7 +547,7 @@ async fn sync_helper(
     }
 }
 
-#[allow(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments, clippy::too_many_lines)]
 async fn load_joined_room(
     sender_user: &UserId,
     sender_device: &DeviceId,
@@ -1154,6 +1155,7 @@ fn share_encrypted_room(
         .any(|encrypted| encrypted))
 }
 
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn sync_events_v4_route(
     body: Ruma<sync_events::v4::Request>,
 ) -> Result<sync_events::v4::Response, RumaResponse<UiaaResponse>> {
diff --git a/src/api/ruma_wrapper/axum.rs b/src/api/ruma_wrapper/axum.rs
index 84209ca7..22931cf2 100644
--- a/src/api/ruma_wrapper/axum.rs
+++ b/src/api/ruma_wrapper/axum.rs
@@ -40,6 +40,7 @@ where
 {
     type Rejection = Error;
 
+    #[allow(clippy::too_many_lines)]
     async fn from_request(req: Request<B>, _state: &S) -> Result<Self, Self::Rejection> {
         #[derive(Deserialize)]
         struct QueryParams {
diff --git a/src/api/server_server.rs b/src/api/server_server.rs
index 41b0db57..daba63ff 100644
--- a/src/api/server_server.rs
+++ b/src/api/server_server.rs
@@ -343,6 +343,7 @@ fn add_port_to_hostname(destination_str: &str) -> FedDest {
 /// Returns: `actual_destination`, `Host` header
 /// Implemented according to the specification at <https://matrix.org/docs/spec/server_server/r0.1.4#resolving-server-names>
 /// Numbers in comments below refer to bullet points in linked section of specification
+#[allow(clippy::too_many_lines)]
 async fn find_actual_destination(destination: &'_ ServerName) -> (FedDest, FedDest) {
     debug!("Finding actual destination for {destination}");
     let destination_str = destination.as_str().to_owned();
@@ -653,6 +654,7 @@ pub(crate) fn parse_incoming_pdu(
 /// # `PUT /_matrix/federation/v1/send/{txnId}`
 ///
 /// Push EDUs and PDUs to this server.
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn send_transaction_message_route(
     body: Ruma<send_transaction_message::v1::Request>,
 ) -> Result<send_transaction_message::v1::Response> {
@@ -1432,6 +1434,7 @@ pub(crate) async fn create_join_event_template_route(
     })
 }
 
+#[allow(clippy::too_many_lines)]
 async fn create_join_event(
     sender_servername: &ServerName,
     room_id: &RoomId,
diff --git a/src/database.rs b/src/database.rs
index d3fda641..3e105120 100644
--- a/src/database.rs
+++ b/src/database.rs
@@ -214,6 +214,7 @@ impl KeyValueDatabase {
         not(any(feature = "rocksdb", feature = "sqlite")),
         allow(unreachable_code)
     )]
+    #[allow(clippy::too_many_lines)]
     pub(crate) async fn load_or_create(config: Config) -> Result<()> {
         Self::check_db_setup(&config)?;
 
diff --git a/src/main.rs b/src/main.rs
index ab06163f..def5a85a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -279,6 +279,7 @@ async fn unrecognized_method<B: Send>(
     Ok(inner)
 }
 
+#[allow(clippy::too_many_lines)]
 fn routes(config: &Config) -> Router {
     let router = Router::new()
         .ruma_route(client_server::get_supported_versions_route)
diff --git a/src/service/admin.rs b/src/service/admin.rs
index 6545c062..1a7cd8aa 100644
--- a/src/service/admin.rs
+++ b/src/service/admin.rs
@@ -327,6 +327,7 @@ impl Service {
         AdminCommand::try_parse_from(argv).map_err(|error| error.to_string())
     }
 
+    #[allow(clippy::too_many_lines)]
     async fn process_admin_command(
         &self,
         command: AdminCommand,
@@ -933,6 +934,7 @@ impl Service {
     ///
     /// Users in this room are considered admins by grapevine, and the room can be
     /// used to issue admin commands by talking to the server user inside it.
+    #[allow(clippy::too_many_lines)]
     pub(crate) async fn create_admin_room(&self) -> Result<()> {
         let room_id = RoomId::new(services().globals.server_name());
 
diff --git a/src/service/rooms/spaces.rs b/src/service/rooms/spaces.rs
index af019e3d..0ffbbf9a 100644
--- a/src/service/rooms/spaces.rs
+++ b/src/service/rooms/spaces.rs
@@ -47,6 +47,7 @@ pub(crate) struct Service {
 }
 
 impl Service {
+    #[allow(clippy::too_many_lines)]
     pub(crate) async fn get_hierarchy(
         &self,
         sender_user: &UserId,
@@ -306,6 +307,7 @@ impl Service {
         })
     }
 
+    #[allow(clippy::too_many_lines)]
     fn get_room_chunk(
         &self,
         sender_user: &UserId,
diff --git a/src/service/rooms/timeline.rs b/src/service/rooms/timeline.rs
index 33cd1889..4dce9420 100644
--- a/src/service/rooms/timeline.rs
+++ b/src/service/rooms/timeline.rs
@@ -607,6 +607,7 @@ impl Service {
         Ok(pdu_id)
     }
 
+    #[allow(clippy::too_many_lines)]
     pub(crate) fn create_hash_and_sign_event(
         &self,
         pdu_builder: PduBuilder,
diff --git a/src/service/users.rs b/src/service/users.rs
index b63e90bb..2e52f478 100644
--- a/src/service/users.rs
+++ b/src/service/users.rs
@@ -57,6 +57,7 @@ impl Service {
             .remove(&(user_id, device_id, conn_id));
     }
 
+    #[allow(clippy::too_many_lines)]
     pub(crate) fn update_sync_request_with_cache(
         &self,
         user_id: OwnedUserId,