diff --git a/crates/ruma-api/tests/manual_endpoint_impl.rs b/crates/ruma-api/tests/manual_endpoint_impl.rs
index 7a810796..87edb4e7 100644
--- a/crates/ruma-api/tests/manual_endpoint_impl.rs
+++ b/crates/ruma-api/tests/manual_endpoint_impl.rs
@@ -18,7 +18,7 @@ use serde::{Deserialize, Serialize};
 /// A request to create a new room alias.
 #[derive(Debug)]
 pub struct Request {
-    pub room_id: RoomId,              // body
+    pub room_id: Box<RoomId>,         // body
     pub room_alias: Box<RoomAliasId>, // path
 }
 
@@ -88,7 +88,7 @@ impl IncomingRequest for Request {
 
 #[derive(Debug, Serialize, Deserialize)]
 struct RequestBody {
-    room_id: RoomId,
+    room_id: Box<RoomId>,
 }
 
 /// The response to a request to create a new room alias.
diff --git a/crates/ruma-appservice-api/src/directory/set_room_visibility.rs b/crates/ruma-appservice-api/src/directory/set_room_visibility.rs
index 6419c687..f7e7d820 100644
--- a/crates/ruma-appservice-api/src/directory/set_room_visibility.rs
+++ b/crates/ruma-appservice-api/src/directory/set_room_visibility.rs
@@ -20,7 +20,7 @@ ruma_api! {
 
         /// Room ID of the room to add or remove from the directory.
         #[ruma_api(path)]
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
 
         /// Whether the room should be visible (public) in the directory or not (private).
         pub visibility: Visibility,
diff --git a/crates/ruma-appservice-api/src/event/push_events/v1.rs b/crates/ruma-appservice-api/src/event/push_events/v1.rs
index 0cd3869b..b199ff2a 100644
--- a/crates/ruma-appservice-api/src/event/push_events/v1.rs
+++ b/crates/ruma-appservice-api/src/event/push_events/v1.rs
@@ -68,7 +68,7 @@ impl IncomingRequest {
 
         #[derive(Debug, Deserialize)]
         struct EventDeHelper {
-            room_id: Option<RoomId>,
+            room_id: Option<Box<RoomId>>,
         }
 
         let mut response = sync_events::Response::new(next_batch.into());
@@ -138,7 +138,7 @@ mod helper_tests {
             incoming_request.try_into_sync_response(txn_id).unwrap();
 
         let response_rooms_join =
-            response.rooms.join.get(&room_id!("!roomid:room.com")).expect("joined room response");
+            response.rooms.join.get(room_id!("!roomid:room.com")).expect("joined room response");
 
         assert_eq!(response_rooms_join.timeline.events.len(), 2);
     }
diff --git a/crates/ruma-client-api/src/r0/alias/get_alias.rs b/crates/ruma-client-api/src/r0/alias/get_alias.rs
index 9b8beaf1..22533fd7 100644
--- a/crates/ruma-client-api/src/r0/alias/get_alias.rs
+++ b/crates/ruma-client-api/src/r0/alias/get_alias.rs
@@ -21,7 +21,7 @@ ruma_api! {
 
     response: {
         /// The room ID for this room alias.
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
 
         /// A list of servers that are aware of this room ID.
         pub servers: Vec<Box<ServerName>>,
@@ -39,7 +39,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room id and servers
-    pub fn new(room_id: RoomId, servers: Vec<Box<ServerName>>) -> Self {
+    pub fn new(room_id: Box<RoomId>, servers: Vec<Box<ServerName>>) -> Self {
         Self { room_id, servers }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/backup/add_backup_keys.rs b/crates/ruma-client-api/src/r0/backup/add_backup_keys.rs
index 57e9c859..cc1758a7 100644
--- a/crates/ruma-client-api/src/r0/backup/add_backup_keys.rs
+++ b/crates/ruma-client-api/src/r0/backup/add_backup_keys.rs
@@ -26,7 +26,7 @@ ruma_api! {
         pub version: &'a str,
 
         /// A map from room IDs to session IDs to key data.
-        pub rooms: BTreeMap<RoomId, RoomKeyBackup>,
+        pub rooms: BTreeMap<Box<RoomId>, RoomKeyBackup>,
     }
 
     response: {
@@ -45,7 +45,7 @@ ruma_api! {
 
 impl<'a> Request<'a> {
     /// Creates a new `Request` with the given version and room key backups.
-    pub fn new(version: &'a str, rooms: BTreeMap<RoomId, RoomKeyBackup>) -> Self {
+    pub fn new(version: &'a str, rooms: BTreeMap<Box<RoomId>, RoomKeyBackup>) -> Self {
         Self { version, rooms }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/backup/get_backup_keys.rs b/crates/ruma-client-api/src/r0/backup/get_backup_keys.rs
index 3bc4b2fd..ec02a48a 100644
--- a/crates/ruma-client-api/src/r0/backup/get_backup_keys.rs
+++ b/crates/ruma-client-api/src/r0/backup/get_backup_keys.rs
@@ -27,7 +27,7 @@ ruma_api! {
 
     response: {
         /// A map from room IDs to session IDs to key data.
-        pub rooms: BTreeMap<RoomId, RoomKeyBackup>,
+        pub rooms: BTreeMap<Box<RoomId>, RoomKeyBackup>,
     }
 
     error: crate::Error
@@ -42,7 +42,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room key backups.
-    pub fn new(rooms: BTreeMap<RoomId, RoomKeyBackup>) -> Self {
+    pub fn new(rooms: BTreeMap<Box<RoomId>, RoomKeyBackup>) -> Self {
         Self { rooms }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/directory.rs b/crates/ruma-client-api/src/r0/directory.rs
index 05e9ffce..cf3792ec 100644
--- a/crates/ruma-client-api/src/r0/directory.rs
+++ b/crates/ruma-client-api/src/r0/directory.rs
@@ -31,7 +31,7 @@ pub struct PublicRoomsChunk {
     pub num_joined_members: UInt,
 
     /// The ID of the room.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The topic of the room, if any.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -68,7 +68,7 @@ impl PublicRoomsChunk {
     /// All other fields will be propagated with default values (an empty list of aliases, `None`
     /// for all `Option`al fields and `false` for all boolean fields), which should be overridden;
     /// the `assign!` macro from the `assign` crate can simplify this.
-    pub fn new(room_id: RoomId) -> Self {
+    pub fn new(room_id: Box<RoomId>) -> Self {
         Self {
             room_id,
             aliases: Vec::new(),
diff --git a/crates/ruma-client-api/src/r0/filter.rs b/crates/ruma-client-api/src/r0/filter.rs
index d4a34db0..70d8fbfe 100644
--- a/crates/ruma-client-api/src/r0/filter.rs
+++ b/crates/ruma-client-api/src/r0/filter.rs
@@ -63,7 +63,7 @@ pub struct RoomEventFilter<'a> {
     /// If this list is absent then no rooms are excluded. A matching room will be excluded even if
     /// it is listed in the 'rooms' filter.
     #[serde(default, skip_serializing_if = "<[_]>::is_empty")]
-    pub not_rooms: &'a [RoomId],
+    pub not_rooms: &'a [Box<RoomId>],
 
     /// The maximum number of events to return.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -73,7 +73,7 @@ pub struct RoomEventFilter<'a> {
     ///
     /// If this list is absent then all rooms are included.
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub rooms: Option<&'a [RoomId]>,
+    pub rooms: Option<&'a [Box<RoomId>]>,
 
     /// A list of sender IDs to exclude.
     ///
@@ -186,14 +186,14 @@ pub struct RoomFilter<'a> {
     /// it is listed in the 'rooms' filter. This filter is applied before the filters in
     /// `ephemeral`, `state`, `timeline` or `account_data`.
     #[serde(default, skip_serializing_if = "<[_]>::is_empty")]
-    pub not_rooms: &'a [RoomId],
+    pub not_rooms: &'a [Box<RoomId>],
 
     /// A list of room IDs to include.
     ///
     /// If this list is absent then all rooms are included. This filter is applied before the
     /// filters in `ephemeral`, `state`, `timeline` or `account_data`.
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub rooms: Option<&'a [RoomId]>,
+    pub rooms: Option<&'a [Box<RoomId>]>,
 }
 
 impl<'a> RoomFilter<'a> {
diff --git a/crates/ruma-client-api/src/r0/knock/knock_room.rs b/crates/ruma-client-api/src/r0/knock/knock_room.rs
index 481326b0..a7318f52 100644
--- a/crates/ruma-client-api/src/r0/knock/knock_room.rs
+++ b/crates/ruma-client-api/src/r0/knock/knock_room.rs
@@ -32,7 +32,7 @@ ruma_api! {
 
     response: {
         /// The room that the user knocked on.
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
     }
 }
 
@@ -45,7 +45,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room ID.
-    pub fn new(room_id: RoomId) -> Self {
+    pub fn new(room_id: Box<RoomId>) -> Self {
         Self { room_id }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/membership/join_room_by_id.rs b/crates/ruma-client-api/src/r0/membership/join_room_by_id.rs
index 0c0036ca..eaa73a0b 100644
--- a/crates/ruma-client-api/src/r0/membership/join_room_by_id.rs
+++ b/crates/ruma-client-api/src/r0/membership/join_room_by_id.rs
@@ -33,7 +33,7 @@ ruma_api! {
 
     response: {
         /// The room that the user joined.
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
     }
 
     error: crate::Error
@@ -53,7 +53,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room id.
-    pub fn new(room_id: RoomId) -> Self {
+    pub fn new(room_id: Box<RoomId>) -> Self {
         Self { room_id }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/membership/join_room_by_id_or_alias.rs b/crates/ruma-client-api/src/r0/membership/join_room_by_id_or_alias.rs
index 39c74382..79090fc2 100644
--- a/crates/ruma-client-api/src/r0/membership/join_room_by_id_or_alias.rs
+++ b/crates/ruma-client-api/src/r0/membership/join_room_by_id_or_alias.rs
@@ -40,7 +40,7 @@ ruma_api! {
 
     response: {
         /// The room that the user joined.
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
     }
 
     error: crate::Error
@@ -61,7 +61,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room ID.
-    pub fn new(room_id: RoomId) -> Self {
+    pub fn new(room_id: Box<RoomId>) -> Self {
         Self { room_id }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/membership/joined_rooms.rs b/crates/ruma-client-api/src/r0/membership/joined_rooms.rs
index 6f4e5c1b..2248cc34 100644
--- a/crates/ruma-client-api/src/r0/membership/joined_rooms.rs
+++ b/crates/ruma-client-api/src/r0/membership/joined_rooms.rs
@@ -19,7 +19,7 @@ ruma_api! {
     response: {
         /// A list of the rooms the user is in, i.e. the ID of each room in
         /// which the user has joined membership.
-        pub joined_rooms: Vec<RoomId>,
+        pub joined_rooms: Vec<Box<RoomId>>,
     }
 
     error: crate::Error
@@ -34,7 +34,7 @@ impl Request {
 
 impl Response {
     /// Creates a new `Response` with the given joined rooms.
-    pub fn new(joined_rooms: Vec<RoomId>) -> Self {
+    pub fn new(joined_rooms: Vec<Box<RoomId>>) -> Self {
         Self { joined_rooms }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/message/get_message_events.rs b/crates/ruma-client-api/src/r0/message/get_message_events.rs
index 1bcefc9d..3fe7f891 100644
--- a/crates/ruma-client-api/src/r0/message/get_message_events.rs
+++ b/crates/ruma-client-api/src/r0/message/get_message_events.rs
@@ -144,20 +144,20 @@ mod tests {
     #[test]
     fn serialize_some_room_event_filter() {
         let room_id = room_id!("!roomid:example.org");
-        let rooms = &[room_id.clone()];
+        let rooms = &[room_id.to_owned()];
         let filter = RoomEventFilter {
             lazy_load_options: LazyLoadOptions::Enabled { include_redundant_members: true },
             rooms: Some(rooms),
             not_rooms: &[
-                room_id!("!room:example.org"),
-                room_id!("!room2:example.org"),
-                room_id!("!room3:example.org"),
+                room_id!("!room:example.org").to_owned(),
+                room_id!("!room2:example.org").to_owned(),
+                room_id!("!room3:example.org").to_owned(),
             ],
             not_types: &["type".into()],
             ..Default::default()
         };
         let req = Request {
-            room_id: &room_id,
+            room_id,
             from: "token",
             to: Some("token2"),
             dir: Direction::Backward,
@@ -185,7 +185,7 @@ mod tests {
     fn serialize_none_room_event_filter() {
         let room_id = room_id!("!roomid:example.org");
         let req = Request {
-            room_id: &room_id,
+            room_id,
             from: "token",
             to: Some("token2"),
             dir: Direction::Backward,
@@ -206,7 +206,7 @@ mod tests {
     fn serialize_default_room_event_filter() {
         let room_id = room_id!("!roomid:example.org");
         let req = Request {
-            room_id: &room_id,
+            room_id,
             from: "token",
             to: Some("token2"),
             dir: Direction::Backward,
diff --git a/crates/ruma-client-api/src/r0/push/get_notifications.rs b/crates/ruma-client-api/src/r0/push/get_notifications.rs
index b505ff5d..7a5a3304 100644
--- a/crates/ruma-client-api/src/r0/push/get_notifications.rs
+++ b/crates/ruma-client-api/src/r0/push/get_notifications.rs
@@ -88,7 +88,7 @@ pub struct Notification {
     pub read: bool,
 
     /// The ID of the room in which the event was posted.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The time at which the event notification was sent.
     pub ts: MilliSecondsSinceUnixEpoch,
@@ -101,7 +101,7 @@ impl Notification {
         actions: Vec<Action>,
         event: Raw<AnySyncRoomEvent>,
         read: bool,
-        room_id: RoomId,
+        room_id: Box<RoomId>,
         ts: MilliSecondsSinceUnixEpoch,
     ) -> Self {
         Self { actions, event, profile_tag: None, read, room_id, ts }
diff --git a/crates/ruma-client-api/src/r0/room/create_room.rs b/crates/ruma-client-api/src/r0/room/create_room.rs
index 0166bb9f..efa94530 100644
--- a/crates/ruma-client-api/src/r0/room/create_room.rs
+++ b/crates/ruma-client-api/src/r0/room/create_room.rs
@@ -92,7 +92,7 @@ ruma_api! {
 
     response: {
         /// The created room's ID.
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
     }
 
     error: crate::Error
@@ -107,7 +107,7 @@ impl Request<'_> {
 
 impl Response {
     /// Creates a new `Response` with the given room id.
-    pub fn new(room_id: RoomId) -> Self {
+    pub fn new(room_id: Box<RoomId>) -> Self {
         Self { room_id }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/room/upgrade_room.rs b/crates/ruma-client-api/src/r0/room/upgrade_room.rs
index 309a0c9a..b76dc102 100644
--- a/crates/ruma-client-api/src/r0/room/upgrade_room.rs
+++ b/crates/ruma-client-api/src/r0/room/upgrade_room.rs
@@ -24,7 +24,7 @@ ruma_api! {
 
     response: {
         /// ID of the new room.
-        pub replacement_room: RoomId,
+        pub replacement_room: Box<RoomId>,
     }
 
     error: crate::Error
@@ -39,7 +39,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room ID.
-    pub fn new(replacement_room: RoomId) -> Self {
+    pub fn new(replacement_room: Box<RoomId>) -> Self {
         Self { replacement_room }
     }
 }
diff --git a/crates/ruma-client-api/src/r0/search/search_events.rs b/crates/ruma-client-api/src/r0/search/search_events.rs
index d6c675ae..ca9e0567 100644
--- a/crates/ruma-client-api/src/r0/search/search_events.rs
+++ b/crates/ruma-client-api/src/r0/search/search_events.rs
@@ -373,7 +373,7 @@ pub struct ResultRoomEvents {
     ///
     /// This is included if the request had the `include_state` key set with a value of `true`.
     #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
-    pub state: BTreeMap<RoomId, Vec<Raw<AnyStateEvent>>>,
+    pub state: BTreeMap<Box<RoomId>, Vec<Raw<AnyStateEvent>>>,
 
     /// List of words which should be highlighted, useful for stemming which may
     /// change the query terms.
@@ -498,7 +498,7 @@ impl UserProfile {
 #[allow(clippy::exhaustive_enums)]
 pub enum RoomIdOrUserId {
     /// Represents a room ID.
-    RoomId(RoomId),
+    RoomId(Box<RoomId>),
 
     /// Represents a user ID.
     UserId(UserId),
diff --git a/crates/ruma-client-api/src/r0/state/get_state_events_for_key.rs b/crates/ruma-client-api/src/r0/state/get_state_events_for_key.rs
index 04ed89a1..497e2a42 100644
--- a/crates/ruma-client-api/src/r0/state/get_state_events_for_key.rs
+++ b/crates/ruma-client-api/src/r0/state/get_state_events_for_key.rs
@@ -123,7 +123,7 @@ impl ruma_api::IncomingRequest for IncomingRequest {
             let decoded =
                 percent_encoding::percent_decode(path_segments[4].as_bytes()).decode_utf8()?;
 
-            RoomId::try_from(&*decoded)?
+            Box::<RoomId>::try_from(&*decoded)?
         };
 
         let event_type = {
diff --git a/crates/ruma-client-api/src/r0/state/send_state_event.rs b/crates/ruma-client-api/src/r0/state/send_state_event.rs
index d9d28af0..af5c7943 100644
--- a/crates/ruma-client-api/src/r0/state/send_state_event.rs
+++ b/crates/ruma-client-api/src/r0/state/send_state_event.rs
@@ -149,7 +149,7 @@ impl ruma_api::IncomingRequest for IncomingRequest {
             let decoded =
                 percent_encoding::percent_decode(path_segments[4].as_bytes()).decode_utf8()?;
 
-            RoomId::try_from(&*decoded)?
+            Box::<RoomId>::try_from(&*decoded)?
         };
 
         let event_type = percent_encoding::percent_decode(path_segments[6].as_bytes())
diff --git a/crates/ruma-client-api/src/r0/sync/sync_events.rs b/crates/ruma-client-api/src/r0/sync/sync_events.rs
index da295625..c37aefd0 100644
--- a/crates/ruma-client-api/src/r0/sync/sync_events.rs
+++ b/crates/ruma-client-api/src/r0/sync/sync_events.rs
@@ -162,20 +162,20 @@ impl<'a> From<&'a str> for Filter<'a> {
 pub struct Rooms {
     /// The rooms that the user has left or been banned from.
     #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
-    pub leave: BTreeMap<RoomId, LeftRoom>,
+    pub leave: BTreeMap<Box<RoomId>, LeftRoom>,
 
     /// The rooms that the user has joined.
     #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
-    pub join: BTreeMap<RoomId, JoinedRoom>,
+    pub join: BTreeMap<Box<RoomId>, JoinedRoom>,
 
     /// The rooms that the user has been invited to.
     #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
-    pub invite: BTreeMap<RoomId, InvitedRoom>,
+    pub invite: BTreeMap<Box<RoomId>, InvitedRoom>,
 
     /// The rooms that the user has knocked on.
     #[cfg(feature = "unstable-pre-spec")]
     #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
-    pub knock: BTreeMap<RoomId, KnockedRoom>,
+    pub knock: BTreeMap<Box<RoomId>, KnockedRoom>,
 }
 
 impl Rooms {
diff --git a/crates/ruma-common/src/directory.rs b/crates/ruma-common/src/directory.rs
index 8574e51c..6d9f4ae2 100644
--- a/crates/ruma-common/src/directory.rs
+++ b/crates/ruma-common/src/directory.rs
@@ -35,7 +35,7 @@ pub struct PublicRoomsChunk {
     pub num_joined_members: UInt,
 
     /// The ID of the room.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The topic of the room, if any.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -72,7 +72,7 @@ pub struct PublicRoomsChunkInit {
     pub num_joined_members: UInt,
 
     /// The ID of the room.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// Whether the room may be viewed by guest users without joining.
     pub world_readable: bool,
diff --git a/crates/ruma-common/src/push.rs b/crates/ruma-common/src/push.rs
index 883255ac..b0f5eb55 100644
--- a/crates/ruma-common/src/push.rs
+++ b/crates/ruma-common/src/push.rs
@@ -966,7 +966,7 @@ mod tests {
         let set = Ruleset::server_default(&user_id!("@jolly_jumper:server.name"));
 
         let context_one_to_one = &PushConditionRoomCtx {
-            room_id: room_id!("!dm:server.name"),
+            room_id: room_id!("!dm:server.name").to_owned(),
             member_count: 2_u32.into(),
             user_display_name: "Jolly Jumper".into(),
             users_power_levels: BTreeMap::new(),
@@ -975,7 +975,7 @@ mod tests {
         };
 
         let context_public_room = &PushConditionRoomCtx {
-            room_id: room_id!("!far_west:server.name"),
+            room_id: room_id!("!far_west:server.name").to_owned(),
             member_count: 100_u32.into(),
             user_display_name: "Jolly Jumper".into(),
             users_power_levels: BTreeMap::new(),
@@ -1065,7 +1065,7 @@ mod tests {
     #[test]
     fn custom_ruleset_applies() {
         let context_one_to_one = &PushConditionRoomCtx {
-            room_id: room_id!("!dm:server.name"),
+            room_id: room_id!("!dm:server.name").to_owned(),
             member_count: 2_u32.into(),
             user_display_name: "Jolly Jumper".into(),
             users_power_levels: BTreeMap::new(),
diff --git a/crates/ruma-common/src/push/condition.rs b/crates/ruma-common/src/push/condition.rs
index c0fa0b5b..8ff0b3d3 100644
--- a/crates/ruma-common/src/push/condition.rs
+++ b/crates/ruma-common/src/push/condition.rs
@@ -116,7 +116,7 @@ impl PushCondition {
 #[allow(clippy::exhaustive_structs)]
 pub struct PushConditionRoomCtx {
     /// The ID of the room.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The number of members in the room.
     pub member_count: UInt,
@@ -484,7 +484,7 @@ mod tests {
         users_power_levels.insert(first_sender, 25.into());
 
         let context = PushConditionRoomCtx {
-            room_id: room_id!("!room:server.name"),
+            room_id: room_id!("!room:server.name").to_owned(),
             member_count: 3_u8.into(),
             user_display_name: "Groovy Gorilla".into(),
             users_power_levels,
diff --git a/crates/ruma-events-macros/src/event.rs b/crates/ruma-events-macros/src/event.rs
index 82814e0e..87541da0 100644
--- a/crates/ruma-events-macros/src/event.rs
+++ b/crates/ruma-events-macros/src/event.rs
@@ -509,7 +509,7 @@ fn expand_sync_from_into_full(
             /// Convert this sync event into a full event, one with a room_id field.
             pub fn into_full_event(
                 self,
-                room_id: #ruma_identifiers::RoomId,
+                room_id: ::std::boxed::Box<#ruma_identifiers::RoomId>,
             ) -> #full_struct #ty_gen {
                 let Self { #( #fields, )* } = self;
                 #full_struct {
diff --git a/crates/ruma-events-macros/src/event_enum.rs b/crates/ruma-events-macros/src/event_enum.rs
index b824219a..9656014b 100644
--- a/crates/ruma-events-macros/src/event_enum.rs
+++ b/crates/ruma-events-macros/src/event_enum.rs
@@ -256,7 +256,7 @@ fn expand_into_full_event(
             /// Convert this sync event into a full event (one with a `room_id` field).
             pub fn into_full_event(
                 self,
-                room_id: #ruma_identifiers::RoomId
+                room_id: ::std::boxed::Box<#ruma_identifiers::RoomId>,
             ) -> #full {
                 match self {
                     #(
diff --git a/crates/ruma-events/src/direct.rs b/crates/ruma-events/src/direct.rs
index e931e9f3..45099efc 100644
--- a/crates/ruma-events/src/direct.rs
+++ b/crates/ruma-events/src/direct.rs
@@ -18,10 +18,10 @@ use serde::{Deserialize, Serialize};
 #[derive(Clone, Debug, Deserialize, Serialize, EventContent)]
 #[allow(clippy::exhaustive_structs)]
 #[ruma_event(type = "m.direct", kind = GlobalAccountData)]
-pub struct DirectEventContent(pub BTreeMap<UserId, Vec<RoomId>>);
+pub struct DirectEventContent(pub BTreeMap<UserId, Vec<Box<RoomId>>>);
 
 impl Deref for DirectEventContent {
-    type Target = BTreeMap<UserId, Vec<RoomId>>;
+    type Target = BTreeMap<UserId, Vec<Box<RoomId>>>;
 
     fn deref(&self) -> &Self::Target {
         &self.0
diff --git a/crates/ruma-events/src/enums.rs b/crates/ruma-events/src/enums.rs
index 758ab706..02e7195a 100644
--- a/crates/ruma-events/src/enums.rs
+++ b/crates/ruma-events/src/enums.rs
@@ -182,7 +182,7 @@ impl AnySyncRoomEvent {
     room_ev_accessor!(sender: &UserId);
 
     /// Converts `self` to an `AnyRoomEvent` by adding the given a room ID.
-    pub fn into_full_event(self, room_id: RoomId) -> AnyRoomEvent {
+    pub fn into_full_event(self, room_id: Box<RoomId>) -> AnyRoomEvent {
         match self {
             Self::Message(ev) => AnyRoomEvent::Message(ev.into_full_event(room_id)),
             Self::State(ev) => AnyRoomEvent::State(ev.into_full_event(room_id)),
diff --git a/crates/ruma-events/src/event_kinds.rs b/crates/ruma-events/src/event_kinds.rs
index 7f85edc8..e614bdf6 100644
--- a/crates/ruma-events/src/event_kinds.rs
+++ b/crates/ruma-events/src/event_kinds.rs
@@ -32,7 +32,7 @@ pub struct EphemeralRoomEvent<C: EphemeralRoomEventContent> {
     pub content: C,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 }
 
 /// An ephemeral room event without a `room_id`.
@@ -61,7 +61,7 @@ pub struct MessageEvent<C: MessageEventContent> {
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// Additional key-value pairs not signed by the homeserver.
     pub unsigned: Unsigned,
@@ -108,7 +108,7 @@ pub struct RedactedMessageEvent<C: RedactedMessageEventContent> {
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// Additional key-value pairs not signed by the homeserver.
     pub unsigned: RedactedUnsigned,
@@ -155,7 +155,7 @@ pub struct StateEvent<C: StateEventContent> {
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// A unique key which defines the overwriting semantics for this piece of room state.
     ///
@@ -252,7 +252,7 @@ pub struct RedactedStateEvent<C: RedactedStateEventContent> {
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// A unique key which defines the overwriting semantics for this piece of room state.
     ///
@@ -335,5 +335,5 @@ pub struct DecryptedMegolmV1Event<C: MessageEventContent> {
     pub content: C,
 
     /// The ID of the room associated with the event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 }
diff --git a/crates/ruma-events/src/forwarded_room_key.rs b/crates/ruma-events/src/forwarded_room_key.rs
index 08a2a2c0..0d413f91 100644
--- a/crates/ruma-events/src/forwarded_room_key.rs
+++ b/crates/ruma-events/src/forwarded_room_key.rs
@@ -16,7 +16,7 @@ pub struct ToDeviceForwardedRoomKeyEventContent {
     pub algorithm: EventEncryptionAlgorithm,
 
     /// The room where the key is used.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The Curve25519 key of the device which initiated the session originally.
     pub sender_key: String,
@@ -54,7 +54,7 @@ pub struct ToDeviceForwardedRoomKeyEventContentInit {
     pub algorithm: EventEncryptionAlgorithm,
 
     /// The room where the key is used.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The Curve25519 key of the device which initiated the session originally.
     pub sender_key: String,
diff --git a/crates/ruma-events/src/pdu.rs b/crates/ruma-events/src/pdu.rs
index acecfd28..a2af16d9 100644
--- a/crates/ruma-events/src/pdu.rs
+++ b/crates/ruma-events/src/pdu.rs
@@ -38,7 +38,7 @@ pub struct RoomV1Pdu {
     pub event_id: Box<EventId>,
 
     /// The room this event belongs to.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The user id of the user who sent this event.
     pub sender: UserId,
@@ -97,7 +97,7 @@ pub struct RoomV1Pdu {
 #[allow(clippy::exhaustive_structs)]
 pub struct RoomV3Pdu {
     /// The room this event belongs to.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The user id of the user who sent this event.
     pub sender: UserId,
diff --git a/crates/ruma-events/src/policy/rule/room.rs b/crates/ruma-events/src/policy/rule/room.rs
index 6cebd2c6..099bb83f 100644
--- a/crates/ruma-events/src/policy/rule/room.rs
+++ b/crates/ruma-events/src/policy/rule/room.rs
@@ -35,7 +35,7 @@ mod tests {
             event_id: event_id!("$143273582443PhrSn:example.org").to_owned(),
             sender: user_id!("@example:example.org"),
             origin_server_ts: MilliSecondsSinceUnixEpoch(1_432_735_824_653_u64.try_into().unwrap()),
-            room_id: room_id!("!jEsUZKDJdhlrceRyVU:example.org"),
+            room_id: room_id!("!jEsUZKDJdhlrceRyVU:example.org").to_owned(),
             state_key: "rule:#*:example.org".into(),
             prev_content: None,
             unsigned: Unsigned {
diff --git a/crates/ruma-events/src/room/canonical_alias.rs b/crates/ruma-events/src/room/canonical_alias.rs
index 2ca05894..4a767457 100644
--- a/crates/ruma-events/src/room/canonical_alias.rs
+++ b/crates/ruma-events/src/room/canonical_alias.rs
@@ -54,7 +54,7 @@ mod tests {
             event_id: event_id!("$h29iv0s8:example.com").to_owned(),
             origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
             prev_content: None,
-            room_id: room_id!("!dummy:example.com"),
+            room_id: room_id!("!dummy:example.com").to_owned(),
             sender: user_id!("@carl:example.com"),
             state_key: "".into(),
             unsigned: Unsigned::default(),
diff --git a/crates/ruma-events/src/room/create.rs b/crates/ruma-events/src/room/create.rs
index 497c99ac..a611a453 100644
--- a/crates/ruma-events/src/room/create.rs
+++ b/crates/ruma-events/src/room/create.rs
@@ -87,7 +87,7 @@ impl RoomType {
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
 pub struct PreviousRoom {
     /// The ID of the old room.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The event ID of the last known event in the old room.
     pub event_id: Box<EventId>,
@@ -95,7 +95,7 @@ pub struct PreviousRoom {
 
 impl PreviousRoom {
     /// Creates a new `PreviousRoom` from the given room and event IDs.
-    pub fn new(room_id: RoomId, event_id: Box<EventId>) -> Self {
+    pub fn new(room_id: Box<RoomId>, event_id: Box<EventId>) -> Self {
         Self { room_id, event_id }
     }
 }
diff --git a/crates/ruma-events/src/room/join_rules.rs b/crates/ruma-events/src/room/join_rules.rs
index fe4300d8..2b03ae5a 100644
--- a/crates/ruma-events/src/room/join_rules.rs
+++ b/crates/ruma-events/src/room/join_rules.rs
@@ -172,7 +172,7 @@ pub enum AllowRule {
 #[cfg(feature = "unstable-pre-spec")]
 impl AllowRule {
     /// Constructs an `AllowRule` with membership of the room with the given id as its predicate.
-    pub fn room_membership(room_id: RoomId) -> Self {
+    pub fn room_membership(room_id: Box<RoomId>) -> Self {
         Self::RoomMembership(RoomMembership::new(room_id))
     }
 }
@@ -183,13 +183,13 @@ impl AllowRule {
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
 pub struct RoomMembership {
     /// The id of the room which being a member of grants permission to join another room.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 }
 
 #[cfg(feature = "unstable-pre-spec")]
 impl RoomMembership {
     /// Constructs a new room membership rule for the given room id.
-    pub fn new(room_id: RoomId) -> Self {
+    pub fn new(room_id: Box<RoomId>) -> Self {
         Self { room_id }
     }
 }
@@ -275,8 +275,8 @@ mod tests {
             JoinRule::Restricted(restricted) => assert_eq!(
                 restricted.allow,
                 &[
-                    AllowRule::room_membership(room_id!("!mods:example.org")),
-                    AllowRule::room_membership(room_id!("!users:example.org"))
+                    AllowRule::room_membership(room_id!("!mods:example.org").to_owned()),
+                    AllowRule::room_membership(room_id!("!users:example.org").to_owned())
                 ]
             ),
             rule => panic!("Deserialized to wrong variant: {:?}", rule),
diff --git a/crates/ruma-events/src/room/message/reply.rs b/crates/ruma-events/src/room/message/reply.rs
index 882311ef..498e1aec 100644
--- a/crates/ruma-events/src/room/message/reply.rs
+++ b/crates/ruma-events/src/room/message/reply.rs
@@ -302,7 +302,7 @@ fn formatted_or_plain_body<'a>(formatted: &'a Option<FormattedBody>, body: &'a s
 mod tests {
     use std::convert::TryFrom;
 
-    use ruma_identifiers::{EventId, RoomId, UserId};
+    use ruma_identifiers::{room_id, EventId, UserId};
 
     use super::RoomMessageEvent;
     use crate::room::message::RoomMessageEventContent;
@@ -316,7 +316,7 @@ mod tests {
                 event_id: EventId::new(sender.server_name()),
                 sender,
                 origin_server_ts: ruma_common::MilliSecondsSinceUnixEpoch::now(),
-                room_id: RoomId::try_from("!n8f893n9:example.com").unwrap(),
+                room_id: room_id!("!n8f893n9:example.com").to_owned(),
                 unsigned: crate::Unsigned::new(),
             }),
             "> <@alice:example.com> multi\n> line"
diff --git a/crates/ruma-events/src/room/name.rs b/crates/ruma-events/src/room/name.rs
index 9b90aef2..d545e88e 100644
--- a/crates/ruma-events/src/room/name.rs
+++ b/crates/ruma-events/src/room/name.rs
@@ -44,7 +44,7 @@ mod tests {
             event_id: event_id!("$h29iv0s8:example.com").to_owned(),
             origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
             prev_content: None,
-            room_id: room_id!("!n8f893n9:example.com"),
+            room_id: room_id!("!n8f893n9:example.com").to_owned(),
             sender: user_id!("@carl:example.com"),
             state_key: "".into(),
             unsigned: Unsigned::default(),
@@ -73,7 +73,7 @@ mod tests {
             event_id: event_id!("$h29iv0s8:example.com").to_owned(),
             origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
             prev_content: Some(RoomNameEventContent { name: "The old name".try_into().ok() }),
-            room_id: room_id!("!n8f893n9:example.com"),
+            room_id: room_id!("!n8f893n9:example.com").to_owned(),
             sender: user_id!("@carl:example.com"),
             state_key: "".into(),
             unsigned: Unsigned { age: Some(int!(100)), ..Unsigned::default() },
diff --git a/crates/ruma-events/src/room/power_levels.rs b/crates/ruma-events/src/room/power_levels.rs
index ebd10b4b..111cf386 100644
--- a/crates/ruma-events/src/room/power_levels.rs
+++ b/crates/ruma-events/src/room/power_levels.rs
@@ -182,7 +182,7 @@ mod tests {
             event_id: event_id!("$h29iv0s8:example.com").to_owned(),
             origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
             prev_content: None,
-            room_id: room_id!("!n8f893n9:example.com"),
+            room_id: room_id!("!n8f893n9:example.com").to_owned(),
             unsigned: Unsigned::default(),
             sender: user_id!("@carl:example.com"),
             state_key: "".into(),
@@ -241,7 +241,7 @@ mod tests {
                 users_default: int!(42),
                 notifications: assign!(NotificationPowerLevels::new(), { room: int!(42) }),
             }),
-            room_id: room_id!("!n8f893n9:example.com"),
+            room_id: room_id!("!n8f893n9:example.com").to_owned(),
             unsigned: Unsigned { age: Some(int!(100)), ..Unsigned::default() },
             sender: user,
             state_key: "".into(),
diff --git a/crates/ruma-events/src/room/redaction.rs b/crates/ruma-events/src/room/redaction.rs
index a524b44e..6c829742 100644
--- a/crates/ruma-events/src/room/redaction.rs
+++ b/crates/ruma-events/src/room/redaction.rs
@@ -27,7 +27,7 @@ pub struct RoomRedactionEvent {
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// Additional key-value pairs not signed by the homeserver.
     pub unsigned: Unsigned,
@@ -74,7 +74,7 @@ pub struct RedactedRoomRedactionEvent {
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
 
     /// The ID of the room associated with this event.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// Additional key-value pairs not signed by the homeserver.
     pub unsigned: RedactedUnsigned,
diff --git a/crates/ruma-events/src/room/tombstone.rs b/crates/ruma-events/src/room/tombstone.rs
index 02f5cd04..147aa58a 100644
--- a/crates/ruma-events/src/room/tombstone.rs
+++ b/crates/ruma-events/src/room/tombstone.rs
@@ -20,12 +20,12 @@ pub struct RoomTombstoneEventContent {
     pub body: String,
 
     /// The new room the client should be visiting.
-    pub replacement_room: RoomId,
+    pub replacement_room: Box<RoomId>,
 }
 
 impl RoomTombstoneEventContent {
     /// Creates a new `RoomTombstoneEventContent` with the given body and replacement room ID.
-    pub fn new(body: String, replacement_room: RoomId) -> Self {
+    pub fn new(body: String, replacement_room: Box<RoomId>) -> Self {
         Self { body, replacement_room }
     }
 }
diff --git a/crates/ruma-events/src/room_key.rs b/crates/ruma-events/src/room_key.rs
index 3bae54cc..07d63ef5 100644
--- a/crates/ruma-events/src/room_key.rs
+++ b/crates/ruma-events/src/room_key.rs
@@ -17,7 +17,7 @@ pub struct ToDeviceRoomKeyEventContent {
     pub algorithm: EventEncryptionAlgorithm,
 
     /// The room where the key is used.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The ID of the session that the key is for.
     pub session_id: String,
@@ -31,7 +31,7 @@ impl ToDeviceRoomKeyEventContent {
     /// and session key.
     pub fn new(
         algorithm: EventEncryptionAlgorithm,
-        room_id: RoomId,
+        room_id: Box<RoomId>,
         session_id: String,
         session_key: String,
     ) -> Self {
@@ -52,7 +52,7 @@ mod tests {
         let ev = ToDeviceEvent {
             content: ToDeviceRoomKeyEventContent {
                 algorithm: EventEncryptionAlgorithm::MegolmV1AesSha2,
-                room_id: room_id!("!testroomid:example.org"),
+                room_id: room_id!("!testroomid:example.org").to_owned(),
                 session_id: "SessId".into(),
                 session_key: "SessKey".into(),
             },
diff --git a/crates/ruma-events/src/room_key_request.rs b/crates/ruma-events/src/room_key_request.rs
index 42ae5d9f..72450be8 100644
--- a/crates/ruma-events/src/room_key_request.rs
+++ b/crates/ruma-events/src/room_key_request.rs
@@ -75,7 +75,7 @@ pub struct RequestedKeyInfo {
     pub algorithm: EventEncryptionAlgorithm,
 
     /// The room where the key is used.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The Curve25519 key of the device which initiated the session originally.
     pub sender_key: String,
@@ -89,7 +89,7 @@ impl RequestedKeyInfo {
     /// ID.
     pub fn new(
         algorithm: EventEncryptionAlgorithm,
-        room_id: RoomId,
+        room_id: Box<RoomId>,
         sender_key: String,
         session_id: String,
     ) -> Self {
diff --git a/crates/ruma-events/tests/custom.rs b/crates/ruma-events/tests/custom.rs
index 7ad01e38..82c5b8f7 100644
--- a/crates/ruma-events/tests/custom.rs
+++ b/crates/ruma-events/tests/custom.rs
@@ -52,7 +52,7 @@ fn serialize_custom_message_event() {
         },
         event_id: event_id!("$h29iv0s8:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(10)),
-        room_id: room_id!("!room:room.com"),
+        room_id: room_id!("!room:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         unsigned: Unsigned::default(),
     };
@@ -93,7 +93,7 @@ fn serialize_custom_state_event() {
         event_id: event_id!("$h29iv0s8:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(10)),
         prev_content: None,
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         state_key: "".into(),
         unsigned: Unsigned::default(),
diff --git a/crates/ruma-events/tests/enums.rs b/crates/ruma-events/tests/enums.rs
index c399729f..98eb9340 100644
--- a/crates/ruma-events/tests/enums.rs
+++ b/crates/ruma-events/tests/enums.rs
@@ -204,7 +204,7 @@ fn message_event_serialization() {
         content: RoomMessageEventContent::text_plain("test"),
         event_id: event_id!("$1234:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(0)),
-        room_id: room_id!("!roomid:example.com"),
+        room_id: room_id!("!roomid:example.com").to_owned(),
         sender: user_id!("@test:example.com"),
         unsigned: Unsigned::default(),
     };
@@ -284,7 +284,7 @@ fn alias_event_field_access() {
         from_json_value::<AnyRoomEvent>(json_data.clone()),
         Ok(AnyRoomEvent::State(state_event))
         if state_event.state_key() == ""
-            && state_event.room_id() == &room_id!("!room:room.com")
+            && state_event.room_id() == room_id!("!room:room.com")
             && state_event.event_id() == event_id!("$152037280074GZeOm:localhost")
             && state_event.sender() == &user_id!("@example:localhost")
     );
@@ -316,7 +316,7 @@ fn ephemeral_event_deserialization() {
     assert_matches!(
         from_json_value::<AnyEphemeralRoomEvent>(json_data),
         Ok(ephem @ AnyEphemeralRoomEvent::Typing(_))
-        if ephem.room_id() == &room_id!("!jEsUZKDJdhlrceRyVU:example.org")
+        if ephem.room_id() == room_id!("!jEsUZKDJdhlrceRyVU:example.org")
     );
 }
 
diff --git a/crates/ruma-events/tests/ephemeral_event.rs b/crates/ruma-events/tests/ephemeral_event.rs
index 0a60a676..dd833ef3 100644
--- a/crates/ruma-events/tests/ephemeral_event.rs
+++ b/crates/ruma-events/tests/ephemeral_event.rs
@@ -15,7 +15,7 @@ use ruma_events::{
 fn ephemeral_serialize_typing() {
     let aliases_event = EphemeralRoomEvent {
         content: TypingEventContent::new(vec![user_id!("@carl:example.com")]),
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
     };
 
     let actual = to_json_value(&aliases_event).unwrap();
@@ -63,7 +63,7 @@ fn ephemeral_serialize_receipt() {
                 },
             },
         }),
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
     };
 
     let actual = to_json_value(&aliases_event).unwrap();
diff --git a/crates/ruma-events/tests/event_enums.rs b/crates/ruma-events/tests/event_enums.rs
index 19db9223..4a3b81fe 100644
--- a/crates/ruma-events/tests/event_enums.rs
+++ b/crates/ruma-events/tests/event_enums.rs
@@ -88,7 +88,7 @@ fn serialize_message_event() {
         ),
         event_id: event_id!("$h29iv0s8:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         unsigned: Unsigned::default(),
     });
diff --git a/crates/ruma-events/tests/message_event.rs b/crates/ruma-events/tests/message_event.rs
index 1aad80bd..a9897a6c 100644
--- a/crates/ruma-events/tests/message_event.rs
+++ b/crates/ruma-events/tests/message_event.rs
@@ -34,7 +34,7 @@ fn message_serialize_sticker() {
         ),
         event_id: event_id!("$h29iv0s8:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         unsigned: Unsigned::default(),
     };
@@ -243,7 +243,7 @@ fn deserialize_message_then_convert_to_full() {
     let sync_ev: AnySyncMessageEvent = from_json_value(json_data).unwrap();
 
     // Test conversion method
-    let full = sync_ev.into_full_event(rid);
+    let full = sync_ev.into_full_event(rid.to_owned());
     let full_json = to_json_value(full).unwrap();
 
     assert_matches!(
diff --git a/crates/ruma-events/tests/pdu.rs b/crates/ruma-events/tests/pdu.rs
index 750fc686..edd791cd 100644
--- a/crates/ruma-events/tests/pdu.rs
+++ b/crates/ruma-events/tests/pdu.rs
@@ -27,7 +27,7 @@ fn serialize_pdu_as_v1() {
     unsigned.insert("somekey".into(), to_raw_json_value(&json!({ "a": 456 })).unwrap());
 
     let v1_pdu = RoomV1Pdu {
-        room_id: room_id!("!n8f893n9:example.com"),
+        room_id: room_id!("!n8f893n9:example.com").to_owned(),
         event_id: event_id!("$somejoinevent:matrix.org").to_owned(),
         sender: user_id!("@sender:example.com"),
         origin: "matrix.org".into(),
@@ -94,7 +94,7 @@ fn serialize_pdu_as_v3() {
     unsigned.insert("somekey".into(), to_raw_json_value(&json!({ "a": 456 })).unwrap());
 
     let v3_pdu = RoomV3Pdu {
-        room_id: room_id!("!n8f893n9:example.com"),
+        room_id: room_id!("!n8f893n9:example.com").to_owned(),
         sender: user_id!("@sender:example.com"),
         origin: "matrix.org".into(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(1_592_050_773_658_u64.try_into().unwrap()),
diff --git a/crates/ruma-events/tests/redaction.rs b/crates/ruma-events/tests/redaction.rs
index 86652760..da57e9f0 100644
--- a/crates/ruma-events/tests/redaction.rs
+++ b/crates/ruma-events/tests/redaction.rs
@@ -31,7 +31,7 @@ fn serialize_redaction() {
         redacts: event_id!("$nomore:example.com").to_owned(),
         event_id: event_id!("$h29iv0s8:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         unsigned: Unsigned::default(),
     };
diff --git a/crates/ruma-events/tests/room_message.rs b/crates/ruma-events/tests/room_message.rs
index d625a6d9..579c07c4 100644
--- a/crates/ruma-events/tests/room_message.rs
+++ b/crates/ruma-events/tests/room_message.rs
@@ -42,7 +42,7 @@ fn serialization() {
         ))),
         event_id: event_id!("$143273582443PhrSn:example.org").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(10_000)),
-        room_id: room_id!("!testroomid:example.org"),
+        room_id: room_id!("!testroomid:example.org").to_owned(),
         sender: user_id!("@user:example.org"),
         unsigned: Unsigned::default(),
     };
diff --git a/crates/ruma-events/tests/state_event.rs b/crates/ruma-events/tests/state_event.rs
index e35d608a..b0e43c86 100644
--- a/crates/ruma-events/tests/state_event.rs
+++ b/crates/ruma-events/tests/state_event.rs
@@ -44,7 +44,7 @@ fn serialize_aliases_with_prev_content() {
         prev_content: Some(RoomAliasesEventContent::new(vec![
             room_alias_id!("#inner:localhost").to_owned()
         ])),
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         state_key: "".into(),
         unsigned: Unsigned::default(),
@@ -65,7 +65,7 @@ fn serialize_aliases_without_prev_content() {
         event_id: event_id!("$h29iv0s8:example.com").to_owned(),
         origin_server_ts: MilliSecondsSinceUnixEpoch(uint!(1)),
         prev_content: None,
-        room_id: room_id!("!roomid:room.com"),
+        room_id: room_id!("!roomid:room.com").to_owned(),
         sender: user_id!("@carl:example.com"),
         state_key: "".into(),
         unsigned: Unsigned::default(),
diff --git a/crates/ruma-events/tests/to_device.rs b/crates/ruma-events/tests/to_device.rs
index 2eba21d8..f077100c 100644
--- a/crates/ruma-events/tests/to_device.rs
+++ b/crates/ruma-events/tests/to_device.rs
@@ -8,7 +8,7 @@ fn serialization() {
         sender: user_id!("@example:example.org"),
         content: ToDeviceRoomKeyEventContent::new(
             EventEncryptionAlgorithm::MegolmV1AesSha2,
-            room_id!("!testroomid:example.org"),
+            room_id!("!testroomid:example.org").to_owned(),
             "SessId".into(),
             "SessKey".into(),
         ),
diff --git a/crates/ruma-events/tests/ui/04-event-sanity-check.rs b/crates/ruma-events/tests/ui/04-event-sanity-check.rs
index d4e40f6c..39182fd7 100644
--- a/crates/ruma-events/tests/ui/04-event-sanity-check.rs
+++ b/crates/ruma-events/tests/ui/04-event-sanity-check.rs
@@ -15,7 +15,7 @@ pub struct StateEvent<C: StateEventContent> {
     pub event_id: Box<EventId>,
     pub sender: UserId,
     pub origin_server_ts: MilliSecondsSinceUnixEpoch,
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
     pub state_key: String,
     pub prev_content: Option<C>,
     pub unsigned: Unsigned,
diff --git a/crates/ruma-federation-api/src/query/get_room_information/v1.rs b/crates/ruma-federation-api/src/query/get_room_information/v1.rs
index 8983babc..54ff9a3d 100644
--- a/crates/ruma-federation-api/src/query/get_room_information/v1.rs
+++ b/crates/ruma-federation-api/src/query/get_room_information/v1.rs
@@ -21,7 +21,7 @@ ruma_api! {
 
     response: {
         /// Room ID mapped to queried alias.
-        pub room_id: RoomId,
+        pub room_id: Box<RoomId>,
 
         /// An array of server names that are likely to hold the given room.
         pub servers: Vec<Box<ServerName>>,
@@ -37,7 +37,7 @@ impl<'a> Request<'a> {
 
 impl Response {
     /// Creates a new `Response` with the given room IDs and servers.
-    pub fn new(room_id: RoomId, servers: Vec<Box<ServerName>>) -> Self {
+    pub fn new(room_id: Box<RoomId>, servers: Vec<Box<ServerName>>) -> Self {
         Self { room_id, servers }
     }
 }
diff --git a/crates/ruma-federation-api/src/thirdparty/bind_callback/v1.rs b/crates/ruma-federation-api/src/thirdparty/bind_callback/v1.rs
index 34406e07..5dade970 100644
--- a/crates/ruma-federation-api/src/thirdparty/bind_callback/v1.rs
+++ b/crates/ruma-federation-api/src/thirdparty/bind_callback/v1.rs
@@ -71,7 +71,7 @@ pub struct ThirdPartyInvite {
     pub mxid: UserId,
 
     /// The room ID the invite is valid for.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The user ID that sent the invite.
     pub sender: UserId,
@@ -85,7 +85,7 @@ impl ThirdPartyInvite {
     pub fn new(
         address: String,
         mxid: UserId,
-        room_id: RoomId,
+        room_id: Box<RoomId>,
         sender: UserId,
         signed: BTreeMap<Box<ServerName>, BTreeMap<ServerSigningKeyId, String>>,
     ) -> Self {
diff --git a/crates/ruma-federation-api/src/transactions/edu.rs b/crates/ruma-federation-api/src/transactions/edu.rs
index 06ec15ab..47658949 100644
--- a/crates/ruma-federation-api/src/transactions/edu.rs
+++ b/crates/ruma-federation-api/src/transactions/edu.rs
@@ -133,12 +133,12 @@ impl PresenceUpdate {
 pub struct ReceiptContent {
     /// Receipts for a particular room.
     #[serde(flatten)]
-    pub receipts: BTreeMap<RoomId, ReceiptMap>,
+    pub receipts: BTreeMap<Box<RoomId>, ReceiptMap>,
 }
 
 impl ReceiptContent {
     /// Creates a new `ReceiptContent`.
-    pub fn new(receipts: BTreeMap<RoomId, ReceiptMap>) -> Self {
+    pub fn new(receipts: BTreeMap<Box<RoomId>, ReceiptMap>) -> Self {
         Self { receipts }
     }
 }
@@ -182,7 +182,7 @@ impl ReceiptData {
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
 pub struct TypingContent {
     /// The room where the user's typing status has been updated.
-    pub room_id: RoomId,
+    pub room_id: Box<RoomId>,
 
     /// The user ID that has had their typing status changed.
     pub user_id: UserId,
@@ -193,7 +193,7 @@ pub struct TypingContent {
 
 impl TypingContent {
     /// Creates a new `TypingContent`.
-    pub fn new(room_id: RoomId, user_id: UserId, typing: bool) -> Self {
+    pub fn new(room_id: Box<RoomId>, user_id: UserId, typing: bool) -> Self {
         Self { room_id, user_id, typing }
     }
 }
@@ -401,7 +401,7 @@ mod test {
         assert_matches!(
             &edu,
             Edu::Receipt(ReceiptContent { receipts })
-                if receipts.get(&room_id!("!some_room:example.org")).is_some()
+                if receipts.get(room_id!("!some_room:example.org")).is_some()
         );
 
         assert_eq!(serde_json::to_value(&edu).unwrap(), json);
diff --git a/crates/ruma-identifiers-macros/src/lib.rs b/crates/ruma-identifiers-macros/src/lib.rs
index f34de542..a49e6c87 100644
--- a/crates/ruma-identifiers-macros/src/lib.rs
+++ b/crates/ruma-identifiers-macros/src/lib.rs
@@ -67,7 +67,7 @@ pub fn room_id(input: TokenStream) -> TokenStream {
     assert!(room_id::validate(&id.value()).is_ok(), "Invalid room_id");
 
     let output = quote! {
-        <#dollar_crate::RoomId as ::std::convert::TryFrom<&str>>::try_from(#id).unwrap()
+        <&#dollar_crate::RoomId as ::std::convert::TryFrom<&str>>::try_from(#id).unwrap()
     };
 
     output.into()
diff --git a/crates/ruma-identifiers-validation/src/room_id.rs b/crates/ruma-identifiers-validation/src/room_id.rs
index cb2fa3f0..476bc77e 100644
--- a/crates/ruma-identifiers-validation/src/room_id.rs
+++ b/crates/ruma-identifiers-validation/src/room_id.rs
@@ -1,7 +1,5 @@
-use std::num::NonZeroU8;
+use crate::{validate_delimited_id, Error};
 
-use crate::{parse_id, Error};
-
-pub fn validate(s: &str) -> Result<NonZeroU8, Error> {
-    parse_id(s, &['!'])
+pub fn validate(s: &str) -> Result<(), Error> {
+    validate_delimited_id(s, &['!'])
 }
diff --git a/crates/ruma-identifiers/src/room_id.rs b/crates/ruma-identifiers/src/room_id.rs
index 731b2f26..12551d38 100644
--- a/crates/ruma-identifiers/src/room_id.rs
+++ b/crates/ruma-identifiers/src/room_id.rs
@@ -1,6 +1,6 @@
 //! Matrix room identifiers.
 
-use std::{convert::TryInto, fmt, num::NonZeroU8};
+use std::convert::TryInto;
 
 use crate::{EventId, MatrixToRef, ServerName};
 
@@ -13,21 +13,14 @@ use crate::{EventId, MatrixToRef, ServerName};
 /// # use std::convert::TryFrom;
 /// # use ruma_identifiers::RoomId;
 /// assert_eq!(
-///     RoomId::try_from("!n8f893n9:example.com").unwrap().as_ref(),
+///     <&RoomId>::try_from("!n8f893n9:example.com").unwrap(),
 ///     "!n8f893n9:example.com"
 /// );
 /// ```
-#[derive(Clone)]
-pub struct RoomId {
-    pub(crate) full_id: Box<str>,
-    pub(crate) colon_idx: NonZeroU8,
-}
+#[repr(transparent)]
+pub struct RoomId(str);
 
-impl fmt::Debug for RoomId {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.full_id.fmt(f)
-    }
-}
+opaque_identifier_validated!(RoomId, ruma_identifiers_validation::room_id::validate);
 
 impl RoomId {
     /// Attempts to generate a `RoomId` for the given origin server with a localpart consisting of
@@ -35,22 +28,18 @@ impl RoomId {
     ///
     /// Fails if the given homeserver cannot be parsed as a valid host.
     #[cfg(feature = "rand")]
-    pub fn new(server_name: &ServerName) -> Self {
-        use crate::generate_localpart;
-
-        let full_id = format!("!{}:{}", generate_localpart(18), server_name).into();
-
-        Self { full_id, colon_idx: NonZeroU8::new(19).unwrap() }
+    pub fn new(server_name: &ServerName) -> Box<Self> {
+        Self::from_owned(format!("!{}:{}", crate::generate_localpart(18), server_name).into())
     }
 
     /// Returns the rooms's unique ID.
     pub fn localpart(&self) -> &str {
-        &self.full_id[1..self.colon_idx.get() as usize]
+        &self.as_str()[1..self.colon_idx()]
     }
 
     /// Returns the server name of the room ID.
     pub fn server_name(&self) -> &ServerName {
-        self.full_id[self.colon_idx.get() as usize + 1..].try_into().unwrap()
+        self.as_str()[self.colon_idx() + 1..].try_into().unwrap()
     }
 
     /// Create a `matrix.to` reference for this room ID.
@@ -71,28 +60,19 @@ impl RoomId {
         &'a self,
         via: impl IntoIterator<Item = &'a ServerName>,
     ) -> MatrixToRef<'a> {
-        MatrixToRef::new(&self.full_id, via.into_iter().collect())
+        MatrixToRef::new(self.as_str(), via.into_iter().collect())
     }
 
     /// Create a `matrix.to` reference for an event scoped under this room ID.
     pub fn matrix_to_event_url<'a>(&'a self, ev_id: &'a EventId) -> MatrixToRef<'a> {
-        MatrixToRef::event(&self.full_id, ev_id, Vec::new())
+        MatrixToRef::event(self.as_str(), ev_id, Vec::new())
+    }
+
+    fn colon_idx(&self) -> usize {
+        self.as_str().find(':').unwrap()
     }
 }
 
-/// Attempts to create a new Matrix room ID from a string representation.
-///
-/// The string must include the leading ! sigil, the localpart, a literal colon, and a server name.
-fn try_from<S>(room_id: S) -> Result<RoomId, crate::Error>
-where
-    S: AsRef<str> + Into<Box<str>>,
-{
-    let colon_idx = ruma_identifiers_validation::room_id::validate(room_id.as_ref())?;
-    Ok(RoomId { full_id: room_id.into(), colon_idx })
-}
-
-common_impls!(RoomId, try_from, "a Matrix room ID");
-
 #[cfg(test)]
 mod tests {
     use std::convert::TryFrom;
@@ -103,7 +83,7 @@ mod tests {
     #[test]
     fn valid_room_id() {
         assert_eq!(
-            RoomId::try_from("!29fhd83h92h0:example.com")
+            <&RoomId>::try_from("!29fhd83h92h0:example.com")
                 .expect("Failed to create RoomId.")
                 .as_ref(),
             "!29fhd83h92h0:example.com"
@@ -113,7 +93,7 @@ mod tests {
     #[test]
     fn empty_localpart() {
         assert_eq!(
-            RoomId::try_from("!:example.com").expect("Failed to create RoomId.").as_ref(),
+            <&RoomId>::try_from("!:example.com").expect("Failed to create RoomId.").as_ref(),
             "!:example.com"
         );
     }
@@ -135,7 +115,7 @@ mod tests {
     fn serialize_valid_room_id() {
         assert_eq!(
             serde_json::to_string(
-                &RoomId::try_from("!29fhd83h92h0:example.com").expect("Failed to create RoomId.")
+                <&RoomId>::try_from("!29fhd83h92h0:example.com").expect("Failed to create RoomId.")
             )
             .expect("Failed to convert RoomId to JSON."),
             r#""!29fhd83h92h0:example.com""#
@@ -146,16 +126,16 @@ mod tests {
     #[test]
     fn deserialize_valid_room_id() {
         assert_eq!(
-            serde_json::from_str::<RoomId>(r#""!29fhd83h92h0:example.com""#)
+            serde_json::from_str::<Box<RoomId>>(r#""!29fhd83h92h0:example.com""#)
                 .expect("Failed to convert JSON to RoomId"),
-            RoomId::try_from("!29fhd83h92h0:example.com").expect("Failed to create RoomId.")
+            <&RoomId>::try_from("!29fhd83h92h0:example.com").expect("Failed to create RoomId.")
         );
     }
 
     #[test]
     fn valid_room_id_with_explicit_standard_port() {
         assert_eq!(
-            RoomId::try_from("!29fhd83h92h0:example.com:443")
+            <&RoomId>::try_from("!29fhd83h92h0:example.com:443")
                 .expect("Failed to create RoomId.")
                 .as_ref(),
             "!29fhd83h92h0:example.com:443"
@@ -165,7 +145,7 @@ mod tests {
     #[test]
     fn valid_room_id_with_non_standard_port() {
         assert_eq!(
-            RoomId::try_from("!29fhd83h92h0:example.com:5000")
+            <&RoomId>::try_from("!29fhd83h92h0:example.com:5000")
                 .expect("Failed to create RoomId.")
                 .as_ref(),
             "!29fhd83h92h0:example.com:5000"
@@ -174,23 +154,26 @@ mod tests {
 
     #[test]
     fn missing_room_id_sigil() {
-        assert_eq!(RoomId::try_from("carl:example.com").unwrap_err(), Error::MissingLeadingSigil);
+        assert_eq!(
+            <&RoomId>::try_from("carl:example.com").unwrap_err(),
+            Error::MissingLeadingSigil
+        );
     }
 
     #[test]
     fn missing_room_id_delimiter() {
-        assert_eq!(RoomId::try_from("!29fhd83h92h0").unwrap_err(), Error::MissingDelimiter);
+        assert_eq!(<&RoomId>::try_from("!29fhd83h92h0").unwrap_err(), Error::MissingDelimiter);
     }
 
     #[test]
     fn invalid_room_id_host() {
-        assert_eq!(RoomId::try_from("!29fhd83h92h0:/").unwrap_err(), Error::InvalidServerName);
+        assert_eq!(<&RoomId>::try_from("!29fhd83h92h0:/").unwrap_err(), Error::InvalidServerName);
     }
 
     #[test]
     fn invalid_room_id_port() {
         assert_eq!(
-            RoomId::try_from("!29fhd83h92h0:example.com:notaport").unwrap_err(),
+            <&RoomId>::try_from("!29fhd83h92h0:example.com:notaport").unwrap_err(),
             Error::InvalidServerName
         );
     }
diff --git a/crates/ruma-identifiers/src/room_id_or_room_alias_id.rs b/crates/ruma-identifiers/src/room_id_or_room_alias_id.rs
index 40ed6f55..7d70fa32 100644
--- a/crates/ruma-identifiers/src/room_id_or_room_alias_id.rs
+++ b/crates/ruma-identifiers/src/room_id_or_room_alias_id.rs
@@ -63,11 +63,9 @@ impl RoomIdOrAliasId {
 
     /// Turn this `RoomIdOrAliasId` into `Either<RoomId, RoomAliasId>`
     #[cfg(feature = "either")]
-    pub fn into_either(self) -> either::Either<RoomId, Box<RoomAliasId>> {
+    pub fn into_either(self) -> either::Either<Box<RoomId>, Box<RoomAliasId>> {
         match self.variant() {
-            Variant::RoomId => {
-                either::Either::Left(RoomId { full_id: self.full_id, colon_idx: self.colon_idx })
-            }
+            Variant::RoomId => either::Either::Left(self.as_str().try_into().unwrap()),
             Variant::RoomAliasId => either::Either::Right(self.as_str().try_into().unwrap()),
         }
     }
@@ -103,9 +101,9 @@ where
 
 common_impls!(RoomIdOrAliasId, try_from, "a Matrix room ID or room alias ID");
 
-impl From<RoomId> for RoomIdOrAliasId {
-    fn from(RoomId { full_id, colon_idx }: RoomId) -> Self {
-        Self { full_id, colon_idx }
+impl From<Box<RoomId>> for RoomIdOrAliasId {
+    fn from(room_id: Box<RoomId>) -> Self {
+        Self::try_from(room_id.as_str()).unwrap()
     }
 }
 
@@ -115,24 +113,24 @@ impl From<Box<RoomAliasId>> for RoomIdOrAliasId {
     }
 }
 
-impl TryFrom<RoomIdOrAliasId> for RoomId {
+impl TryFrom<RoomIdOrAliasId> for Box<RoomId> {
     type Error = Box<RoomAliasId>;
 
-    fn try_from(id: RoomIdOrAliasId) -> Result<RoomId, Box<RoomAliasId>> {
+    fn try_from(id: RoomIdOrAliasId) -> Result<Box<RoomId>, Box<RoomAliasId>> {
         match id.variant() {
-            Variant::RoomId => Ok(RoomId { full_id: id.full_id, colon_idx: id.colon_idx }),
+            Variant::RoomId => Ok(id.as_str().try_into().unwrap()),
             Variant::RoomAliasId => Err(id.as_str().try_into().unwrap()),
         }
     }
 }
 
 impl TryFrom<RoomIdOrAliasId> for Box<RoomAliasId> {
-    type Error = RoomId;
+    type Error = Box<RoomId>;
 
-    fn try_from(id: RoomIdOrAliasId) -> Result<Box<RoomAliasId>, RoomId> {
+    fn try_from(id: RoomIdOrAliasId) -> Result<Box<RoomAliasId>, Box<RoomId>> {
         match id.variant() {
             Variant::RoomAliasId => Ok(id.as_str().try_into().unwrap()),
-            Variant::RoomId => Err(RoomId { full_id: id.full_id, colon_idx: id.colon_idx }),
+            Variant::RoomId => Err(id.as_str().try_into().unwrap()),
         }
     }
 }
diff --git a/crates/ruma-push-gateway-api/src/send_event_notification/v1.rs b/crates/ruma-push-gateway-api/src/send_event_notification/v1.rs
index 50c2866a..00c77950 100644
--- a/crates/ruma-push-gateway-api/src/send_event_notification/v1.rs
+++ b/crates/ruma-push-gateway-api/src/send_event_notification/v1.rs
@@ -364,7 +364,7 @@ mod tests {
 
         let notice = Notification {
             event_id: Some(eid),
-            room_id: Some(&rid),
+            room_id: Some(rid),
             event_type: Some(&EventType::RoomMessage),
             sender: Some(&uid),
             sender_display_name: Some("Major Tom"),
diff --git a/crates/ruma-serde-macros/src/outgoing.rs b/crates/ruma-serde-macros/src/outgoing.rs
index 835bd141..1af077ab 100644
--- a/crates/ruma-serde-macros/src/outgoing.rs
+++ b/crates/ruma-serde-macros/src/outgoing.rs
@@ -268,6 +268,7 @@ fn strip_lifetimes(field_type: &mut Type) -> bool {
                         || last_seg.ident == "SessionId"
                         || last_seg.ident == "RawJsonValue"
                         || last_seg.ident == "RoomAliasId"
+                        || last_seg.ident == "RoomId"
                         || last_seg.ident == "RoomName"
                     {
                         // The identifiers that need to be boxed `Box<T>` since they are DST's.
diff --git a/crates/ruma-state-res/benches/state_res_bench.rs b/crates/ruma-state-res/benches/state_res_bench.rs
index 13453d46..12290ea7 100644
--- a/crates/ruma-state-res/benches/state_res_bench.rs
+++ b/crates/ruma-state-res/benches/state_res_bench.rs
@@ -29,7 +29,7 @@ use ruma_events::{
     },
     EventType,
 };
-use ruma_identifiers::{EventId, RoomId, RoomVersionId, UserId};
+use ruma_identifiers::{room_id, EventId, RoomId, RoomVersionId, UserId};
 use ruma_state_res::{self as state_res, Error, Event, Result, StateMap};
 use serde_json::{
     json,
@@ -71,7 +71,7 @@ fn resolution_shallow_auth_chain(c: &mut Criterion) {
                 state_sets
                     .iter()
                     .map(|map| {
-                        store.auth_event_ids(&room_id(), map.values().cloned().collect()).unwrap()
+                        store.auth_event_ids(room_id(), map.values().cloned().collect()).unwrap()
                     })
                     .collect(),
                 |id| ev_map.get(id).map(Arc::clone),
@@ -135,7 +135,7 @@ fn resolve_deeper_event_set(c: &mut Criterion) {
                 state_sets
                     .iter()
                     .map(|map| {
-                        store.auth_event_ids(&room_id(), map.values().cloned().collect()).unwrap()
+                        store.auth_event_ids(room_id(), map.values().cloned().collect()).unwrap()
                     })
                     .collect(),
                 |id| inner.get(id).map(Arc::clone),
@@ -355,8 +355,8 @@ fn ella() -> UserId {
     UserId::try_from("@ella:foo").unwrap()
 }
 
-fn room_id() -> RoomId {
-    RoomId::try_from("!test:foo").unwrap()
+fn room_id() -> &'static RoomId {
+    room_id!("!test:foo")
 }
 
 fn member_content_ban() -> Box<RawJsonValue> {
@@ -390,7 +390,7 @@ where
     Arc::new(StateEvent {
         event_id: id.try_into().unwrap(),
         rest: Pdu::RoomV3Pdu(RoomV3Pdu {
-            room_id: room_id(),
+            room_id: room_id().to_owned(),
             sender,
             origin_server_ts: MilliSecondsSinceUnixEpoch(ts.try_into().unwrap()),
             state_key,
diff --git a/crates/ruma-state-res/src/lib.rs b/crates/ruma-state-res/src/lib.rs
index 1e8f570c..8d51ec17 100644
--- a/crates/ruma-state-res/src/lib.rs
+++ b/crates/ruma-state-res/src/lib.rs
@@ -1044,7 +1044,7 @@ mod tests {
             state_sets
                 .iter()
                 .map(|map| {
-                    store.auth_event_ids(&room_id(), map.values().cloned().collect()).unwrap()
+                    store.auth_event_ids(room_id(), map.values().cloned().collect()).unwrap()
                 })
                 .collect(),
             |id| ev_map.get(id).map(Arc::clone),
@@ -1148,7 +1148,7 @@ mod tests {
             state_sets
                 .iter()
                 .map(|map| {
-                    store.auth_event_ids(&room_id(), map.values().cloned().collect()).unwrap()
+                    store.auth_event_ids(room_id(), map.values().cloned().collect()).unwrap()
                 })
                 .collect(),
             |id| ev_map.get(id).map(Arc::clone),
diff --git a/crates/ruma-state-res/src/test_utils.rs b/crates/ruma-state-res/src/test_utils.rs
index b595836d..9b83eae2 100644
--- a/crates/ruma-state-res/src/test_utils.rs
+++ b/crates/ruma-state-res/src/test_utils.rs
@@ -112,7 +112,7 @@ pub fn do_check(
             let auth_chain_sets = state_sets
                 .iter()
                 .map(|map| {
-                    store.auth_event_ids(&room_id(), map.values().cloned().collect()).unwrap()
+                    store.auth_event_ids(room_id(), map.values().cloned().collect()).unwrap()
                 })
                 .collect();
 
@@ -367,7 +367,7 @@ pub fn zara() -> UserId {
     user_id!("@zara:foo")
 }
 
-pub fn room_id() -> RoomId {
+pub fn room_id() -> &'static RoomId {
     room_id!("!test:foo")
 }
 
@@ -393,7 +393,7 @@ pub fn to_init_pdu_event(
     Arc::new(StateEvent {
         event_id: id.try_into().unwrap(),
         rest: Pdu::RoomV3Pdu(RoomV3Pdu {
-            room_id: room_id(),
+            room_id: room_id().to_owned(),
             sender,
             origin_server_ts: MilliSecondsSinceUnixEpoch(ts.try_into().unwrap()),
             state_key,
@@ -433,7 +433,7 @@ where
     Arc::new(StateEvent {
         event_id: id.try_into().unwrap(),
         rest: Pdu::RoomV3Pdu(RoomV3Pdu {
-            room_id: room_id(),
+            room_id: room_id().to_owned(),
             sender,
             origin_server_ts: MilliSecondsSinceUnixEpoch(ts.try_into().unwrap()),
             state_key,