diff --git a/src/session/content/room_details/invite_subpage/invitee_list.rs b/src/session/content/room_details/invite_subpage/invitee_list.rs
index ccc31e5b..ac6f4195 100644
--- a/src/session/content/room_details/invite_subpage/invitee_list.rs
+++ b/src/session/content/room_details/invite_subpage/invitee_list.rs
@@ -2,6 +2,7 @@ use gtk::{gio, glib, glib::clone, prelude::*, subclass::prelude::*};
 use log::error;
 use matrix_sdk::ruma::{api::client::r0::user_directory::search_users, identifiers::UserId};
 use matrix_sdk::HttpError;
+use std::sync::Arc;
 
 use crate::session::user::UserExt;
 use crate::{session::Room, spawn, spawn_tokio};
@@ -40,7 +41,7 @@ mod imp {
         pub room: OnceCell<Room>,
         pub state: Cell<InviteeListState>,
         pub search_term: RefCell<Option<String>>,
-        pub invitee_list: RefCell<HashMap<Box<UserId>, Invitee>>,
+        pub invitee_list: RefCell<HashMap<Arc<UserId>, Invitee>>,
         pub abort_handle: RefCell<Option<AbortHandle>>,
     }
 
@@ -244,7 +245,7 @@ impl InviteeList {
                     .filter_map(|item| {
                         // Skip over users that are already in the room
                         if member_list.contains(&item.user_id) {
-                            self.remove_invitee(&item.user_id);
+                            self.remove_invitee(item.user_id.into());
                             None
                         } else if let Some(user) = self.get_invitee(&item.user_id) {
                             // The avatar or the display name may have changed in the mean time
@@ -333,7 +334,7 @@ impl InviteeList {
         priv_
             .invitee_list
             .borrow_mut()
-            .insert(user.user_id().to_owned(), user.clone());
+            .insert(user.user_id(), user.clone());
         self.emit_by_name("invitee-added", &[&user]).unwrap();
         self.notify("has-selected");
     }
@@ -348,9 +349,9 @@ impl InviteeList {
             .collect()
     }
 
-    fn remove_invitee(&self, user_id: &UserId) {
+    fn remove_invitee(&self, user_id: Arc<UserId>) {
         let priv_ = imp::InviteeList::from_instance(self);
-        let removed = priv_.invitee_list.borrow_mut().remove(user_id);
+        let removed = priv_.invitee_list.borrow_mut().remove(&user_id);
         if let Some(user) = removed {
             user.set_invited(false);
             self.emit_by_name("invitee-removed", &[&user]).unwrap();
diff --git a/src/session/mod.rs b/src/session/mod.rs
index 1304430e..32e6ba06 100644
--- a/src/session/mod.rs
+++ b/src/session/mod.rs
@@ -397,7 +397,7 @@ impl Session {
                     match handle.await.unwrap() {
                         Ok((display_name, avatar_url)) => {
                             user.set_display_name(display_name);
-                            user.set_avatar_url(avatar_url)
+                            user.set_avatar_url(avatar_url);
                         }
                         Err(error) => error!("Couldn’t fetch account metadata: {}", error),
                     }
@@ -500,7 +500,7 @@ impl Session {
     fn mark_ready(&self) {
         let priv_ = imp::Session::from_instance(self);
         let client = self.client();
-        let user_id = self.user().unwrap().user_id().to_owned();
+        let user_id = self.user().unwrap().user_id();
 
         priv_.is_ready.set(true);
 
diff --git a/src/session/room/event.rs b/src/session/room/event.rs
index df466648..105f46df 100644
--- a/src/session/room/event.rs
+++ b/src/session/room/event.rs
@@ -15,6 +15,7 @@ use matrix_sdk::{
     },
     Error as MatrixError,
 };
+use std::sync::Arc;
 
 use crate::{
     session::{room::Member, Room},
@@ -174,7 +175,7 @@ impl Event {
     }
 
     pub fn sender(&self) -> Member {
-        self.room().members().member_by_id(&self.matrix_sender())
+        self.room().members().member_by_id(self.matrix_sender())
     }
 
     pub fn room(&self) -> Room {
@@ -210,11 +211,11 @@ impl Event {
         self.notify("can-view-media");
     }
 
-    pub fn matrix_sender(&self) -> Box<UserId> {
+    pub fn matrix_sender(&self) -> Arc<UserId> {
         let priv_ = imp::Event::from_instance(self);
 
         if let Some(event) = priv_.event.borrow().as_ref() {
-            event.sender().to_owned()
+            event.sender().into()
         } else {
             priv_
                 .pure_event
@@ -222,7 +223,7 @@ impl Event {
                 .as_ref()
                 .unwrap()
                 .event
-                .get_field::<Box<UserId>>("sender")
+                .get_field::<Arc<UserId>>("sender")
                 .unwrap()
                 .unwrap()
         }
diff --git a/src/session/room/item.rs b/src/session/room/item.rs
index 9359c715..46ca8449 100644
--- a/src/session/room/item.rs
+++ b/src/session/room/item.rs
@@ -3,6 +3,7 @@ use matrix_sdk::ruma::{
     events::AnySyncRoomEvent,
     identifiers::{EventId, UserId},
 };
+use std::sync::Arc;
 
 use crate::session::room::Event;
 
@@ -182,7 +183,7 @@ impl Item {
         }
     }
 
-    pub fn matrix_sender(&self) -> Option<Box<UserId>> {
+    pub fn matrix_sender(&self) -> Option<Arc<UserId>> {
         let priv_ = imp::Item::from_instance(self);
         if let ItemType::Event(event) = priv_.type_.get().unwrap() {
             Some(event.matrix_sender())
diff --git a/src/session/room/member.rs b/src/session/room/member.rs
index dfc3f73a..1af7a0f8 100644
--- a/src/session/room/member.rs
+++ b/src/session/room/member.rs
@@ -98,7 +98,7 @@ impl Member {
 
     /// Update the user based on the the room member state event
     pub fn update_from_room_member(&self, member: &RoomMember) {
-        if member.user_id() != self.user_id() {
+        if member.user_id() != &*self.user_id() {
             log::error!("Tried Member update from RoomMember with wrong user ID.");
             return;
         };
@@ -111,7 +111,7 @@ impl Member {
 
     /// Update the user based on the the room member state event
     pub fn update_from_member_event(&self, event: &impl MemberEvent) {
-        if event.sender() != self.user_id() {
+        if event.sender() != &*self.user_id() {
             log::error!("Tried Member update from MemberEvent with wrong user ID.");
             return;
         };
diff --git a/src/session/room/member_list.rs b/src/session/room/member_list.rs
index 5158eb1a..756d9f3f 100644
--- a/src/session/room/member_list.rs
+++ b/src/session/room/member_list.rs
@@ -1,7 +1,7 @@
+use crate::session::room::{Member, Room, UserId};
 use gtk::{gio, glib, prelude::*, subclass::prelude::*};
 use indexmap::IndexMap;
-
-use crate::session::room::{Member, Room, UserId};
+use std::sync::Arc;
 
 use matrix_sdk::ruma::events::{room::member::RoomMemberEventContent, SyncStateEvent};
 
@@ -13,7 +13,7 @@ mod imp {
 
     #[derive(Debug, Default)]
     pub struct MemberList {
-        pub members: RefCell<IndexMap<Box<UserId>, Member>>,
+        pub members: RefCell<IndexMap<Arc<UserId>, Member>>,
         pub room: OnceCell<WeakRef<Room>>,
     }
 
@@ -108,8 +108,8 @@ impl MemberList {
         let prev_len = members.len();
         for member in new_members {
             members
-                .entry(member.user_id().to_owned())
-                .or_insert_with(|| Member::new(&self.room(), member.user_id()))
+                .entry(member.user_id().into())
+                .or_insert_with_key(|user_id| Member::new(&self.room(), user_id))
                 .update_from_room_member(&member);
         }
         let num_members_added = members.len().saturating_sub(prev_len);
@@ -126,13 +126,13 @@ impl MemberList {
     /// Returns the member with the given ID.
     ///
     /// Creates a new member first if there is no member with the given ID.
-    pub fn member_by_id(&self, user_id: &UserId) -> Member {
+    pub fn member_by_id(&self, user_id: Arc<UserId>) -> Member {
         let mut members = imp::MemberList::from_instance(self).members.borrow_mut();
         let mut was_member_added = false;
         let prev_len = members.len();
         let member = members
-            .entry(user_id.to_owned())
-            .or_insert_with(|| {
+            .entry(user_id)
+            .or_insert_with_key(|user_id| {
                 was_member_added = true;
                 Member::new(&self.room(), user_id)
             })
@@ -153,7 +153,7 @@ impl MemberList {
     ///
     /// Creates a new member first if there is no member matching the given event.
     pub fn update_member_for_member_event(&self, event: &SyncStateEvent<RoomMemberEventContent>) {
-        self.member_by_id(&event.sender)
+        self.member_by_id(event.sender.clone().into())
             .update_from_member_event(event);
     }
 
diff --git a/src/session/room/mod.rs b/src/session/room/mod.rs
index 3dd37614..a17b3e8d 100644
--- a/src/session/room/mod.rs
+++ b/src/session/room/mod.rs
@@ -51,6 +51,7 @@ use serde_json::value::RawValue;
 use std::cell::RefCell;
 use std::convert::TryInto;
 use std::path::PathBuf;
+use std::sync::Arc;
 
 use crate::components::{LabelWithWidgets, Pill};
 use crate::prelude::*;
@@ -851,7 +852,7 @@ impl Room {
         let event = AnySyncMessageEvent::RoomMessage(SyncMessageEvent {
             content: content.clone(),
             event_id: EventId::parse(format!("${}:fractal.gnome.org", txn_id).as_str()).unwrap(),
-            sender: self.session().user().unwrap().user_id().to_owned(),
+            sender: self.session().user().unwrap().user_id().as_ref().to_owned(),
             origin_server_ts: MilliSecondsSinceUnixEpoch::now(),
             unsigned: Unsigned::default(),
         });
@@ -1075,8 +1076,7 @@ impl Room {
 
     pub async fn invite(&self, users: &[User]) {
         let matrix_room = self.matrix_room();
-        let user_ids: Vec<Box<UserId>> =
-            users.iter().map(|user| user.user_id().to_owned()).collect();
+        let user_ids: Vec<Arc<UserId>> = users.iter().map(|user| user.user_id()).collect();
 
         if let MatrixRoom::Joined(matrix_room) = matrix_room {
             let handle = spawn_tokio!(async move {
diff --git a/src/session/room/timeline.rs b/src/session/room/timeline.rs
index 67ffada1..7c757995 100644
--- a/src/session/room/timeline.rs
+++ b/src/session/room/timeline.rs
@@ -714,12 +714,12 @@ impl Timeline {
 
                     let user = session.user().unwrap();
 
-                    let user_to_verify = if &request.to == user.user_id() {
+                    let user_to_verify = if &*request.to == &*user.user_id() {
                         // The request was sent by another user to verify us
                         event.sender()
-                    } else if &message.sender == user.user_id() {
+                    } else if &*message.sender == &*user.user_id() {
                         // The request was sent by us to verify another user
-                        self.room().members().member_by_id(&request.to)
+                        self.room().members().member_by_id(request.to.into())
                     } else {
                         // Ignore the request when it doesn't verify us or wasn't set by us
                         return;
@@ -745,25 +745,25 @@ impl Timeline {
                 return;
             }
             AnySyncMessageEvent::KeyVerificationReady(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             AnySyncMessageEvent::KeyVerificationStart(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             AnySyncMessageEvent::KeyVerificationCancel(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             AnySyncMessageEvent::KeyVerificationAccept(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             AnySyncMessageEvent::KeyVerificationKey(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             AnySyncMessageEvent::KeyVerificationMac(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             AnySyncMessageEvent::KeyVerificationDone(e) => {
-                FlowId::new(e.sender, e.content.relates_to.event_id.to_string())
+                FlowId::new(e.sender.into(), e.content.relates_to.event_id.to_string())
             }
             _ => {
                 return;
diff --git a/src/session/user.rs b/src/session/user.rs
index 94aaae0a..1a53bb3e 100644
--- a/src/session/user.rs
+++ b/src/session/user.rs
@@ -4,6 +4,7 @@ use matrix_sdk::ruma::identifiers::{MxcUri, UserId};
 use crate::session::{Avatar, Session};
 use crate::spawn_tokio;
 use matrix_sdk::encryption::identities::UserIdentity;
+use std::sync::Arc;
 
 use log::error;
 
@@ -11,11 +12,11 @@ mod imp {
     use super::*;
     use glib::object::WeakRef;
     use once_cell::{sync::Lazy, unsync::OnceCell};
-    use std::{cell::RefCell, convert::TryInto};
+    use std::cell::RefCell;
 
     #[derive(Debug, Default)]
     pub struct User {
-        pub user_id: OnceCell<Box<UserId>>,
+        pub user_id: OnceCell<Arc<UserId>>,
         pub display_name: RefCell<Option<String>>,
         pub session: OnceCell<WeakRef<Session>>,
         pub avatar: OnceCell<Avatar>,
@@ -75,8 +76,9 @@ mod imp {
         ) {
             match pspec.name() {
                 "user-id" => {
-                    let user_id = value.get::<&str>().unwrap().try_into().unwrap();
-                    self.user_id.set(user_id).unwrap();
+                    self.user_id
+                        .set(UserId::parse_arc(value.get::<&str>().unwrap()).unwrap())
+                        .unwrap();
                 }
                 "display-name" => {
                     obj.set_display_name(value.get::<Option<String>>().unwrap());
@@ -126,7 +128,7 @@ impl User {
 
     pub async fn crypto_identity(&self) -> Option<UserIdentity> {
         let client = self.session().client();
-        let user_id = self.user_id().to_owned();
+        let user_id = self.user_id();
         let handle = spawn_tokio!(async move { client.get_user_identity(&user_id).await });
 
         match handle.await.unwrap() {
@@ -145,9 +147,9 @@ pub trait UserExt: IsA<User> {
         priv_.session.get().unwrap().upgrade().unwrap()
     }
 
-    fn user_id(&self) -> &UserId {
+    fn user_id(&self) -> Arc<UserId> {
         let priv_ = imp::User::from_instance(self.upcast_ref());
-        priv_.user_id.get().unwrap()
+        priv_.user_id.get().unwrap().clone()
     }
 
     fn display_name(&self) -> String {
diff --git a/src/session/verification/identity_verification.rs b/src/session/verification/identity_verification.rs
index d74a7c65..e188ee91 100644
--- a/src/session/verification/identity_verification.rs
+++ b/src/session/verification/identity_verification.rs
@@ -400,7 +400,7 @@ impl IdentityVerification {
         };
 
         let client = self.session().client();
-        let user_id = self.user().user_id().to_owned();
+        let user_id = self.user().user_id();
         let flow_id = self.flow_id().to_owned();
 
         let (sync_sender, sync_receiver) = mpsc::channel(100);
diff --git a/src/session/verification/verification_list.rs b/src/session/verification/verification_list.rs
index ce07d0a7..22984e2a 100644
--- a/src/session/verification/verification_list.rs
+++ b/src/session/verification/verification_list.rs
@@ -8,15 +8,16 @@ use log::{debug, warn};
 use matrix_sdk::ruma::{
     api::client::r0::sync::sync_events::ToDevice, events::AnyToDeviceEvent, identifiers::UserId,
 };
+use std::sync::Arc;
 
 #[derive(Hash, PartialEq, Eq, Debug)]
 pub struct FlowId {
-    user_id: Box<UserId>,
+    user_id: Arc<UserId>,
     flow_id: String,
 }
 
 impl FlowId {
-    pub fn new(user_id: Box<UserId>, flow_id: String) -> Self {
+    pub fn new(user_id: Arc<UserId>, flow_id: String) -> Self {
         Self { user_id, flow_id }
     }
 }
@@ -118,14 +119,14 @@ impl VerificationList {
             debug!("Received verification event: {:?}", event);
             let request = match event {
                 AnyToDeviceEvent::KeyVerificationRequest(e) => {
-                    let flow_id = FlowId::new(e.sender, e.content.transaction_id);
+                    let flow_id = FlowId::new(e.sender.into(), e.content.transaction_id);
                     if let Some(request) = self.get_by_id(&flow_id) {
                         Some(request)
                     } else {
                         let session = self.session();
                         let user = session.user().unwrap();
                         // ToDevice verifications can only be send by us
-                        if &flow_id.user_id != user.user_id() {
+                        if flow_id.user_id != user.user_id() {
                             warn!("Received a device verification event from a different user, which isn't allowed");
                             continue;
                         }
@@ -168,25 +169,25 @@ impl VerificationList {
                     }
                 }
                 AnyToDeviceEvent::KeyVerificationReady(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 AnyToDeviceEvent::KeyVerificationStart(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 AnyToDeviceEvent::KeyVerificationCancel(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 AnyToDeviceEvent::KeyVerificationAccept(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 AnyToDeviceEvent::KeyVerificationMac(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 AnyToDeviceEvent::KeyVerificationKey(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 AnyToDeviceEvent::KeyVerificationDone(e) => {
-                    self.get_by_id(&FlowId::new(e.sender, e.content.transaction_id))
+                    self.get_by_id(&FlowId::new(e.sender.into(), e.content.transaction_id))
                 }
                 _ => continue,
             };
@@ -220,10 +221,7 @@ impl VerificationList {
             );
 
             list.insert(
-                FlowId::new(
-                    request.user().user_id().to_owned(),
-                    request.flow_id().to_owned(),
-                ),
+                FlowId::new(request.user().user_id(), request.flow_id().to_owned()),
                 request,
             );
             length as u32
@@ -234,11 +232,9 @@ impl VerificationList {
     pub fn remove(&self, request: &IdentityVerification) {
         let priv_ = imp::VerificationList::from_instance(self);
 
-        let position = if let Some((position, _, _)) =
-            priv_.list.borrow_mut().shift_remove_full(&FlowId::new(
-                request.user().user_id().to_owned(),
-                request.flow_id().to_owned(),
-            )) {
+        let position = if let Some((position, _, _)) = priv_.list.borrow_mut().shift_remove_full(
+            &FlowId::new(request.user().user_id(), request.flow_id().to_owned()),
+        ) {
             position
         } else {
             return;