diff --git a/matrix_sdk/src/client.rs b/matrix_sdk/src/client.rs
index 52f6188e..d1968b02 100644
--- a/matrix_sdk/src/client.rs
+++ b/matrix_sdk/src/client.rs
@@ -27,8 +27,6 @@ use std::{
 
 #[cfg(feature = "encryption")]
 use dashmap::DashMap;
-#[cfg(feature = "encryption")]
-use futures::TryStreamExt;
 use futures_timer::Delay as sleep;
 use http::HeaderValue;
 use mime::{self, Mime};
@@ -1155,10 +1153,10 @@ impl Client {
             let _guard = mutex.lock().await;
 
             {
-                let room = self.get_joined_room(room_id).unwrap();
-                let members = room.joined_user_ids().await;
-                let members_iter: Vec<UserId> = members.try_collect().await?;
-                self.claim_one_time_keys(&mut members_iter.iter()).await?;
+                let joined = self.store().get_joined_user_ids(room_id).await?;
+                let invited = self.store().get_invited_user_ids(room_id).await?;
+                let members = joined.iter().chain(&invited);
+                self.claim_one_time_keys(members).await?;
             };
 
             let response = self.share_group_session(room_id).await;
@@ -1831,7 +1829,7 @@ impl Client {
     #[cfg(feature = "encryption")]
     #[cfg_attr(feature = "docs", doc(cfg(encryption)))]
     #[instrument(skip(users))]
-    async fn claim_one_time_keys(&self, users: &mut impl Iterator<Item = &UserId>) -> Result<()> {
+    async fn claim_one_time_keys(&self, users: impl Iterator<Item = &UserId>) -> Result<()> {
         let _lock = self.key_claim_lock.lock().await;
 
         if let Some((request_id, request)) = self.base_client.get_missing_sessions(users).await? {
@@ -2277,7 +2275,6 @@ mod test {
         get_public_rooms, get_public_rooms_filtered, register::RegistrationKind, Client,
         Invite3pid, Session, SyncSettings, Url,
     };
-    use futures::TryStreamExt;
     use matrix_sdk_base::RoomMember;
     use matrix_sdk_common::{
         api::r0::{
@@ -2893,7 +2890,7 @@ mod test {
         let room = client
             .get_joined_room(&room_id!("!SVkFJHzfwvuaIEawgC:localhost"))
             .unwrap();
-        let members: Vec<RoomMember> = room.active_members().await.try_collect().await.unwrap();
+        let members: Vec<RoomMember> = room.active_members().await.unwrap();
 
         assert_eq!(1, members.len());
         // assert!(room.power_levels.is_some())
diff --git a/matrix_sdk_base/examples/state_inspector.rs b/matrix_sdk_base/examples/state_inspector.rs
index a91a64bb..f4b5b35d 100644
--- a/matrix_sdk_base/examples/state_inspector.rs
+++ b/matrix_sdk_base/examples/state_inspector.rs
@@ -1,6 +1,6 @@
 use std::{convert::TryFrom, fmt::Debug, io, sync::Arc};
 
-use futures::{executor::block_on, TryStreamExt};
+use futures::executor::block_on;
 use serde::Serialize;
 
 use atty::Stream;
@@ -86,14 +86,7 @@ impl InspectorHelper {
     }
 
     fn complete_rooms(&self, arg: Option<&&str>) -> Vec<Pair> {
-        let rooms: Vec<RoomInfo> = block_on(async {
-            self.store
-                .get_room_infos()
-                .await
-                .try_collect()
-                .await
-                .unwrap()
-        });
+        let rooms: Vec<RoomInfo> = block_on(async { self.store.get_room_infos().await.unwrap() });
 
         rooms
             .into_iter()
@@ -286,24 +279,12 @@ impl Inspector {
     }
 
     async fn list_rooms(&self) {
-        let rooms: Vec<RoomInfo> = self
-            .store
-            .get_room_infos()
-            .await
-            .try_collect()
-            .await
-            .unwrap();
+        let rooms: Vec<RoomInfo> = self.store.get_room_infos().await.unwrap();
         self.printer.pretty_print_struct(&rooms);
     }
 
     async fn get_profiles(&self, room_id: RoomId) {
-        let joined: Vec<UserId> = self
-            .store
-            .get_joined_user_ids(&room_id)
-            .await
-            .try_collect()
-            .await
-            .unwrap();
+        let joined: Vec<UserId> = self.store.get_joined_user_ids(&room_id).await.unwrap();
 
         for member in joined {
             let event = self.store.get_profile(&room_id, &member).await.unwrap();
@@ -312,13 +293,7 @@ impl Inspector {
     }
 
     async fn get_members(&self, room_id: RoomId) {
-        let joined: Vec<UserId> = self
-            .store
-            .get_joined_user_ids(&room_id)
-            .await
-            .try_collect()
-            .await
-            .unwrap();
+        let joined: Vec<UserId> = self.store.get_joined_user_ids(&room_id).await.unwrap();
 
         for member in joined {
             let event = self
diff --git a/matrix_sdk_base/src/client.rs b/matrix_sdk_base/src/client.rs
index ef0e3957..b406e5ba 100644
--- a/matrix_sdk_base/src/client.rs
+++ b/matrix_sdk_base/src/client.rs
@@ -23,8 +23,6 @@ use std::{
     time::SystemTime,
 };
 
-#[cfg(feature = "encryption")]
-use futures::{StreamExt, TryStreamExt};
 use matrix_sdk_common::{
     api::r0 as api,
     deserialized_responses::{
@@ -762,11 +760,11 @@ impl BaseClient {
                         // The room turned on encryption in this sync, we need
                         // to get also all the existing users and mark them for
                         // tracking.
-                        let joined = self.store.get_joined_user_ids(&room_id).await;
-                        let invited = self.store.get_invited_user_ids(&room_id).await;
+                        let joined = self.store.get_joined_user_ids(&room_id).await?;
+                        let invited = self.store.get_invited_user_ids(&room_id).await?;
 
-                        let user_ids: Vec<UserId> = joined.chain(invited).try_collect().await?;
-                        o.update_tracked_users(&user_ids).await
+                        let user_ids = joined.iter().chain(&invited);
+                        o.update_tracked_users(user_ids).await
                     }
 
                     o.update_tracked_users(&user_ids).await
@@ -1030,7 +1028,7 @@ impl BaseClient {
     #[cfg_attr(feature = "docs", doc(cfg(encryption)))]
     pub async fn get_missing_sessions(
         &self,
-        users: &mut impl Iterator<Item = &UserId>,
+        users: impl Iterator<Item = &UserId>,
     ) -> Result<Option<(Uuid, KeysClaimRequest)>> {
         let olm = self.olm.lock().await;
 
@@ -1048,11 +1046,11 @@ impl BaseClient {
 
         match &*olm {
             Some(o) => {
-                let joined = self.store.get_joined_user_ids(room_id).await;
-                let invited = self.store.get_invited_user_ids(room_id).await;
-                let members: Vec<UserId> = joined.chain(invited).try_collect().await?;
+                let joined = self.store.get_joined_user_ids(room_id).await?;
+                let invited = self.store.get_invited_user_ids(room_id).await?;
+                let members = joined.iter().chain(&invited);
                 Ok(
-                    o.share_group_session(room_id, members.iter(), EncryptionSettings::default())
+                    o.share_group_session(room_id, members, EncryptionSettings::default())
                         .await?,
                 )
             }
diff --git a/matrix_sdk_base/src/rooms/normal.rs b/matrix_sdk_base/src/rooms/normal.rs
index 73e73bf3..481386c8 100644
--- a/matrix_sdk_base/src/rooms/normal.rs
+++ b/matrix_sdk_base/src/rooms/normal.rs
@@ -19,7 +19,7 @@ use std::{
 
 use futures::{
     future,
-    stream::{self, Stream, StreamExt, TryStreamExt},
+    stream::{self, StreamExt},
 };
 use matrix_sdk_common::{
     api::r0::sync::sync_events::RoomSummary as RumaSummary,
@@ -38,7 +38,7 @@ use tracing::info;
 
 use crate::{
     deserialized_responses::UnreadNotificationsCount,
-    store::{Result as StoreResult, SledStore},
+    store::{Result as StoreResult, StateStore},
 };
 
 use super::{BaseRoomInfo, RoomMember};
@@ -48,7 +48,7 @@ pub struct Room {
     room_id: Arc<RoomId>,
     own_user_id: Arc<UserId>,
     inner: Arc<SyncRwLock<RoomInfo>>,
-    store: SledStore,
+    store: Arc<Box<dyn StateStore>>,
 }
 
 #[derive(Clone, Debug, Default, Serialize, Deserialize)]
@@ -72,7 +72,7 @@ pub enum RoomType {
 impl Room {
     pub(crate) fn new(
         own_user_id: &UserId,
-        store: SledStore,
+        store: Arc<Box<dyn StateStore>>,
         room_id: &RoomId,
         room_type: RoomType,
     ) -> Self {
@@ -91,7 +91,11 @@ impl Room {
         Self::restore(own_user_id, store, room_info)
     }
 
-    pub(crate) fn restore(own_user_id: &UserId, store: SledStore, room_info: RoomInfo) -> Self {
+    pub(crate) fn restore(
+        own_user_id: &UserId,
+        store: Arc<Box<dyn StateStore>>,
+        room_info: RoomInfo,
+    ) -> Self {
         Self {
             own_user_id: Arc::new(own_user_id.clone()),
             room_id: room_info.room_id.clone(),
@@ -197,35 +201,40 @@ impl Room {
         self.calculate_name().await
     }
 
-    pub async fn joined_user_ids(&self) -> impl Stream<Item = StoreResult<UserId>> {
+    pub async fn joined_user_ids(&self) -> StoreResult<Vec<UserId>> {
         self.store.get_joined_user_ids(self.room_id()).await
     }
 
-    pub async fn joined_members(&self) -> impl Stream<Item = StoreResult<RoomMember>> + '_ {
-        let joined = self.store.get_joined_user_ids(self.room_id()).await;
+    pub async fn joined_members(&self) -> StoreResult<Vec<RoomMember>> {
+        let joined = self.store.get_joined_user_ids(self.room_id()).await?;
+        let mut members = Vec::new();
 
-        joined.filter_map(move |u| async move {
-            let ret = match u {
-                Ok(u) => self.get_member(&u).await,
-                Err(e) => Err(e),
-            };
+        for u in joined {
+            let m = self.get_member(&u).await?;
 
-            ret.transpose()
-        })
+            if let Some(member) = m {
+                members.push(member);
+            }
+        }
+
+        Ok(members)
     }
 
-    pub async fn active_members(&self) -> impl Stream<Item = StoreResult<RoomMember>> + '_ {
-        let joined = self.store.get_joined_user_ids(self.room_id()).await;
-        let invited = self.store.get_invited_user_ids(self.room_id()).await;
+    pub async fn active_members(&self) -> StoreResult<Vec<RoomMember>> {
+        let joined = self.store.get_joined_user_ids(self.room_id()).await?;
+        let invited = self.store.get_invited_user_ids(self.room_id()).await?;
 
-        joined.chain(invited).filter_map(move |u| async move {
-            let ret = match u {
-                Ok(u) => self.get_member(&u).await,
-                Err(e) => Err(e),
-            };
+        let mut members = Vec::new();
 
-            ret.transpose()
-        })
+        for u in joined.iter().chain(&invited) {
+            let m = self.get_member(u).await?;
+
+            if let Some(member) = m {
+                members.push(member);
+            }
+        }
+
+        Ok(members)
     }
 
     /// Calculate the canonical display name of the room, taking into account
@@ -257,13 +266,13 @@ impl Room {
         let is_own_member = |m: &RoomMember| m.user_id() == &*self.own_user_id;
         let is_own_user_id = |u: &str| u == self.own_user_id().as_str();
 
-        let members: StoreResult<Vec<RoomMember>> = if summary.heroes.is_empty() {
+        let members: Vec<RoomMember> = if summary.heroes.is_empty() {
             self.active_members()
-                .await
-                .try_filter(|u| future::ready(!is_own_member(&u)))
+                .await?
+                .into_iter()
+                .filter(|u| !is_own_member(&u))
                 .take(5)
-                .try_collect()
-                .await
+                .collect()
         } else {
             let members: Vec<_> = stream::iter(summary.heroes.iter())
                 .filter(|u| future::ready(!is_own_user_id(u)))
@@ -274,7 +283,9 @@ impl Room {
                 .collect()
                 .await;
 
-            members.into_iter().collect()
+            let members: StoreResult<Vec<_>> = members.into_iter().collect();
+
+            members?
         };
 
         info!(
@@ -288,7 +299,7 @@ impl Room {
         let inner = self.inner.read().unwrap();
         Ok(inner
             .base_info
-            .calculate_room_name(joined, invited, members?))
+            .calculate_room_name(joined, invited, members))
     }
 
     pub(crate) fn clone_info(&self) -> RoomInfo {
diff --git a/matrix_sdk_base/src/rooms/stripped.rs b/matrix_sdk_base/src/rooms/stripped.rs
index 61a9e677..67610806 100644
--- a/matrix_sdk_base/src/rooms/stripped.rs
+++ b/matrix_sdk_base/src/rooms/stripped.rs
@@ -20,7 +20,7 @@ use matrix_sdk_common::{
 };
 use serde::{Deserialize, Serialize};
 
-use crate::store::SledStore;
+use crate::store::StateStore;
 
 use super::BaseRoomInfo;
 
@@ -29,11 +29,11 @@ pub struct StrippedRoom {
     room_id: Arc<RoomId>,
     own_user_id: Arc<UserId>,
     inner: Arc<SyncMutex<StrippedRoomInfo>>,
-    store: SledStore,
+    store: Arc<Box<dyn StateStore>>,
 }
 
 impl StrippedRoom {
-    pub fn new(own_user_id: &UserId, store: SledStore, room_id: &RoomId) -> Self {
+    pub fn new(own_user_id: &UserId, store: Arc<Box<dyn StateStore>>, room_id: &RoomId) -> Self {
         let room_id = Arc::new(room_id.clone());
 
         Self {
diff --git a/matrix_sdk_base/src/store/mod.rs b/matrix_sdk_base/src/store/mod.rs
index 196aaf48..9cb24673 100644
--- a/matrix_sdk_base/src/store/mod.rs
+++ b/matrix_sdk_base/src/store/mod.rs
@@ -15,14 +15,15 @@
 use std::{collections::BTreeMap, ops::Deref, path::Path, sync::Arc};
 
 use dashmap::DashMap;
-use futures::stream::StreamExt;
 use matrix_sdk_common::{
+    async_trait,
     events::{
         presence::PresenceEvent, room::member::MemberEventContent, AnyBasicEvent,
-        AnyStrippedStateEvent, AnySyncStateEvent, EventContent,
+        AnyStrippedStateEvent, AnySyncStateEvent, EventContent, EventType,
     },
     identifiers::{RoomId, UserId},
     locks::RwLock,
+    AsyncTraitDeps,
 };
 
 use crate::{
@@ -53,9 +54,48 @@ pub enum StoreError {
 /// A `StateStore` specific result type.
 pub type Result<T> = std::result::Result<T, StoreError>;
 
+#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
+#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
+pub trait StateStore: AsyncTraitDeps {
+    async fn save_filter(&self, filter_name: &str, filter_id: &str) -> Result<()>;
+
+    async fn save_changes(&self, changes: &StateChanges) -> Result<()>;
+
+    async fn get_filter(&self, filter_id: &str) -> Result<Option<String>>;
+
+    async fn get_sync_token(&self) -> Result<Option<String>>;
+
+    async fn get_presence_event(&self, user_id: &UserId) -> Result<Option<PresenceEvent>>;
+
+    async fn get_state_event(
+        &self,
+        room_id: &RoomId,
+        event_type: EventType,
+        state_key: &str,
+    ) -> Result<Option<AnySyncStateEvent>>;
+
+    async fn get_profile(
+        &self,
+        room_id: &RoomId,
+        user_id: &UserId,
+    ) -> Result<Option<MemberEventContent>>;
+
+    async fn get_member_event(
+        &self,
+        room_id: &RoomId,
+        state_key: &UserId,
+    ) -> Result<Option<MemberEvent>>;
+
+    async fn get_invited_user_ids(&self, room_id: &RoomId) -> Result<Vec<UserId>>;
+
+    async fn get_joined_user_ids(&self, room_id: &RoomId) -> Result<Vec<UserId>>;
+
+    async fn get_room_infos(&self) -> Result<Vec<RoomInfo>>;
+}
+
 #[derive(Debug, Clone)]
 pub struct Store {
-    inner: SledStore,
+    inner: Arc<Box<dyn StateStore>>,
     session: Arc<RwLock<Option<Session>>>,
     sync_token: Arc<RwLock<Option<String>>>,
     rooms: Arc<DashMap<RoomId, Room>>,
@@ -69,7 +109,7 @@ impl Store {
         inner: SledStore,
     ) -> Self {
         Self {
-            inner,
+            inner: Arc::new(Box::new(inner)),
             session,
             sync_token,
             rooms: DashMap::new().into(),
@@ -78,11 +118,8 @@ impl Store {
     }
 
     pub(crate) async fn restore_session(&self, session: Session) -> Result<()> {
-        let mut infos = self.inner.get_room_infos().await;
-
-        // TODO restore stripped rooms.
-        while let Some(info) = infos.next().await {
-            let room = Room::restore(&session.user_id, self.inner.clone(), info?);
+        for info in self.inner.get_room_infos().await?.into_iter() {
+            let room = Room::restore(&session.user_id, self.inner.clone(), info);
             self.rooms.insert(room.room_id().to_owned(), room);
         }
 
@@ -172,7 +209,7 @@ impl Store {
 }
 
 impl Deref for Store {
-    type Target = SledStore;
+    type Target = Box<dyn StateStore>;
 
     fn deref(&self) -> &Self::Target {
         &self.inner
diff --git a/matrix_sdk_base/src/store/sled_store/mod.rs b/matrix_sdk_base/src/store/sled_store/mod.rs
index 8affb114..b65c24c9 100644
--- a/matrix_sdk_base/src/store/sled_store/mod.rs
+++ b/matrix_sdk_base/src/store/sled_store/mod.rs
@@ -16,8 +16,12 @@ mod store_key;
 
 use std::{convert::TryFrom, path::Path, sync::Arc, time::SystemTime};
 
-use futures::stream::{self, Stream};
+use futures::{
+    stream::{self, Stream},
+    TryStreamExt,
+};
 use matrix_sdk_common::{
+    async_trait,
     events::{
         presence::PresenceEvent,
         room::member::{MemberEventContent, MembershipState},
@@ -37,7 +41,7 @@ use crate::deserialized_responses::MemberEvent;
 
 use self::store_key::{EncryptedEvent, StoreKey};
 
-use super::{Result, RoomInfo, StateChanges, StoreError};
+use super::{Result, RoomInfo, StateChanges, StateStore, StoreError};
 
 #[derive(Debug, Serialize, Deserialize)]
 pub enum DatabaseType {
@@ -477,6 +481,66 @@ impl SledStore {
     }
 }
 
+#[async_trait]
+impl StateStore for SledStore {
+    async fn save_filter(&self, filter_name: &str, filter_id: &str) -> Result<()> {
+        self.save_filter(filter_name, filter_id).await
+    }
+
+    async fn save_changes(&self, changes: &StateChanges) -> Result<()> {
+        self.save_changes(changes).await
+    }
+
+    async fn get_filter(&self, filter_id: &str) -> Result<Option<String>> {
+        self.get_filter(filter_id).await
+    }
+
+    async fn get_sync_token(&self) -> Result<Option<String>> {
+        self.get_sync_token().await
+    }
+
+    async fn get_presence_event(&self, user_id: &UserId) -> Result<Option<PresenceEvent>> {
+        self.get_presence_event(user_id).await
+    }
+
+    async fn get_state_event(
+        &self,
+        room_id: &RoomId,
+        event_type: EventType,
+        state_key: &str,
+    ) -> Result<Option<AnySyncStateEvent>> {
+        self.get_state_event(room_id, event_type, state_key).await
+    }
+
+    async fn get_profile(
+        &self,
+        room_id: &RoomId,
+        user_id: &UserId,
+    ) -> Result<Option<MemberEventContent>> {
+        self.get_profile(room_id, user_id).await
+    }
+
+    async fn get_member_event(
+        &self,
+        room_id: &RoomId,
+        state_key: &UserId,
+    ) -> Result<Option<MemberEvent>> {
+        self.get_member_event(room_id, state_key).await
+    }
+
+    async fn get_invited_user_ids(&self, room_id: &RoomId) -> Result<Vec<UserId>> {
+        self.get_invited_user_ids(room_id).await.try_collect().await
+    }
+
+    async fn get_joined_user_ids(&self, room_id: &RoomId) -> Result<Vec<UserId>> {
+        self.get_joined_user_ids(room_id).await.try_collect().await
+    }
+
+    async fn get_room_infos(&self) -> Result<Vec<RoomInfo>> {
+        self.get_room_infos().await.try_collect().await
+    }
+}
+
 #[cfg(test)]
 mod test {
     use std::{convert::TryFrom, time::SystemTime};
diff --git a/matrix_sdk_crypto/src/machine.rs b/matrix_sdk_crypto/src/machine.rs
index 59fe3bb1..f6bdf31c 100644
--- a/matrix_sdk_crypto/src/machine.rs
+++ b/matrix_sdk_crypto/src/machine.rs
@@ -502,7 +502,7 @@ impl OlmMachine {
     /// [`mark_request_as_sent`]: #method.mark_request_as_sent
     pub async fn get_missing_sessions(
         &self,
-        users: &mut impl Iterator<Item = &UserId>,
+        users: impl Iterator<Item = &UserId>,
     ) -> OlmResult<Option<(Uuid, KeysClaimRequest)>> {
         self.session_manager.get_missing_sessions(users).await
     }
diff --git a/matrix_sdk_crypto/src/session_manager/sessions.rs b/matrix_sdk_crypto/src/session_manager/sessions.rs
index 95afe118..311cb572 100644
--- a/matrix_sdk_crypto/src/session_manager/sessions.rs
+++ b/matrix_sdk_crypto/src/session_manager/sessions.rs
@@ -188,7 +188,7 @@ impl SessionManager {
     /// [`receive_keys_claim_response`]: #method.receive_keys_claim_response
     pub async fn get_missing_sessions(
         &self,
-        users: &mut impl Iterator<Item = &UserId>,
+        users: impl Iterator<Item = &UserId>,
     ) -> OlmResult<Option<(Uuid, KeysClaimRequest)>> {
         let mut missing = BTreeMap::new();