diff --git a/matrix_sdk_base/examples/state_inspector.rs b/matrix_sdk_base/examples/state_inspector.rs
index f4b5b35d..e0688b12 100644
--- a/matrix_sdk_base/examples/state_inspector.rs
+++ b/matrix_sdk_base/examples/state_inspector.rs
@@ -247,7 +247,7 @@ impl Printer {
 impl Inspector {
     fn new(database_path: &str, json: bool, color: bool) -> Self {
         let printer = Printer::new(json, color);
-        let store = Store::open_default(database_path).unwrap();
+        let store = Store::open_default(database_path, None).unwrap();
 
         Self { store, printer }
     }
diff --git a/matrix_sdk_base/src/client.rs b/matrix_sdk_base/src/client.rs
index 6c34912f..d56ef51b 100644
--- a/matrix_sdk_base/src/client.rs
+++ b/matrix_sdk_base/src/client.rs
@@ -61,7 +61,7 @@ use crate::{
     event_emitter::Emitter,
     rooms::{RoomInfo, RoomType, StrippedRoomInfo},
     session::Session,
-    store::{Result as StoreResult, SledStore, StateChanges, Store},
+    store::{Result as StoreResult, StateChanges, Store},
     EventEmitter, RoomState,
 };
 
@@ -280,24 +280,19 @@ impl BaseClient {
     /// previous login call.
     pub fn new_with_config(config: BaseClientConfig) -> Result<Self> {
         let store = if let Some(path) = &config.store_path {
-            if let Some(passphrase) = &config.passphrase {
+            if config.passphrase.is_some() {
                 info!("Opening an encrypted store in path {}", path.display());
-                SledStore::open_with_passphrase(path, passphrase)?
             } else {
                 info!("Opening store in path {}", path.display());
-                SledStore::open_with_path(path)?
             }
+            Store::open_default(path, config.passphrase.as_deref().map(|p| p.as_str()))?
         } else {
-            SledStore::open()?
+            Store::open_temporrary()?
         };
 
-        let session = Arc::new(RwLock::new(None));
-        let sync_token = Arc::new(RwLock::new(None));
-        let store = Store::new(session.clone(), sync_token.clone(), store);
-
         Ok(BaseClient {
-            session,
-            sync_token,
+            session: store.session.clone(),
+            sync_token: store.sync_token.clone(),
             store,
             #[cfg(feature = "encryption")]
             olm: Mutex::new(None).into(),
diff --git a/matrix_sdk_base/src/store/memory_store.rs b/matrix_sdk_base/src/store/memory_store.rs
new file mode 100644
index 00000000..fa3db415
--- /dev/null
+++ b/matrix_sdk_base/src/store/memory_store.rs
@@ -0,0 +1,341 @@
+// Copyright 2021 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::{
+    sync::{Arc, RwLock},
+    time::SystemTime,
+};
+
+use dashmap::{DashMap, DashSet};
+use matrix_sdk_common::{
+    async_trait,
+    events::{
+        presence::PresenceEvent,
+        room::member::{MemberEventContent, MembershipState},
+        AnyBasicEvent, AnyStrippedStateEvent, AnySyncStateEvent, EventContent, EventType,
+    },
+    identifiers::{RoomId, UserId},
+};
+
+use tracing::info;
+
+use crate::deserialized_responses::{MemberEvent, StrippedMemberEvent};
+
+use super::{Result, RoomInfo, StateChanges, StateStore, StrippedRoomInfo};
+
+#[derive(Debug, Clone)]
+pub struct MemoryStore {
+    sync_token: Arc<RwLock<Option<String>>>,
+    filters: Arc<DashMap<String, String>>,
+    account_data: Arc<DashMap<String, AnyBasicEvent>>,
+    members: Arc<DashMap<RoomId, DashMap<UserId, MemberEvent>>>,
+    profiles: Arc<DashMap<RoomId, DashMap<UserId, MemberEventContent>>>,
+    joined_user_ids: Arc<DashMap<RoomId, DashSet<UserId>>>,
+    invited_user_ids: Arc<DashMap<RoomId, DashSet<UserId>>>,
+    room_info: Arc<DashMap<RoomId, RoomInfo>>,
+    #[allow(clippy::type_complexity)]
+    room_state: Arc<DashMap<RoomId, DashMap<String, DashMap<String, AnySyncStateEvent>>>>,
+    room_account_data: Arc<DashMap<RoomId, DashMap<String, AnyBasicEvent>>>,
+    stripped_room_info: Arc<DashMap<RoomId, StrippedRoomInfo>>,
+    #[allow(clippy::type_complexity)]
+    stripped_room_state:
+        Arc<DashMap<RoomId, DashMap<String, DashMap<String, AnyStrippedStateEvent>>>>,
+    stripped_members: Arc<DashMap<RoomId, DashMap<UserId, StrippedMemberEvent>>>,
+    presence: Arc<DashMap<UserId, PresenceEvent>>,
+}
+
+impl MemoryStore {
+    pub fn new() -> Self {
+        Self {
+            sync_token: Arc::new(RwLock::new(None)),
+            filters: DashMap::new().into(),
+            account_data: DashMap::new().into(),
+            members: DashMap::new().into(),
+            profiles: DashMap::new().into(),
+            joined_user_ids: DashMap::new().into(),
+            invited_user_ids: DashMap::new().into(),
+            room_info: DashMap::new().into(),
+            room_state: DashMap::new().into(),
+            room_account_data: DashMap::new().into(),
+            stripped_room_info: DashMap::new().into(),
+            stripped_room_state: DashMap::new().into(),
+            stripped_members: DashMap::new().into(),
+            presence: DashMap::new().into(),
+        }
+    }
+
+    pub async fn save_filter(&self, filter_name: &str, filter_id: &str) -> Result<()> {
+        self.filters
+            .insert(filter_name.to_string(), filter_id.to_string());
+
+        Ok(())
+    }
+
+    pub async fn get_filter(&self, filter_name: &str) -> Result<Option<String>> {
+        Ok(self.filters.get(filter_name).map(|f| f.to_string()))
+    }
+
+    pub async fn get_sync_token(&self) -> Result<Option<String>> {
+        Ok(self.sync_token.read().unwrap().clone())
+    }
+
+    pub async fn save_changes(&self, changes: &StateChanges) -> Result<()> {
+        let now = SystemTime::now();
+
+        if let Some(s) = &changes.sync_token {
+            *self.sync_token.write().unwrap() = Some(s.to_owned());
+        }
+
+        for (room, events) in &changes.members {
+            for event in events.values() {
+                match event.content.membership {
+                    MembershipState::Join => {
+                        self.joined_user_ids
+                            .entry(room.clone())
+                            .or_insert_with(DashSet::new)
+                            .insert(event.state_key.clone());
+                        self.invited_user_ids
+                            .entry(room.clone())
+                            .or_insert_with(DashSet::new)
+                            .remove(&event.state_key);
+                    }
+                    MembershipState::Invite => {
+                        self.invited_user_ids
+                            .entry(room.clone())
+                            .or_insert_with(DashSet::new)
+                            .insert(event.state_key.clone());
+                        self.joined_user_ids
+                            .entry(room.clone())
+                            .or_insert_with(DashSet::new)
+                            .remove(&event.state_key);
+                    }
+                    _ => {
+                        self.joined_user_ids
+                            .entry(room.clone())
+                            .or_insert_with(DashSet::new)
+                            .remove(&event.state_key);
+                        self.invited_user_ids
+                            .entry(room.clone())
+                            .or_insert_with(DashSet::new)
+                            .remove(&event.state_key);
+                    }
+                }
+
+                self.members
+                    .entry(room.clone())
+                    .or_insert_with(DashMap::new)
+                    .insert(event.state_key.clone(), event.clone());
+            }
+        }
+
+        for (room, users) in &changes.profiles {
+            for (user_id, profile) in users {
+                self.profiles
+                    .entry(room.clone())
+                    .or_insert_with(DashMap::new)
+                    .insert(user_id.clone(), profile.clone());
+            }
+        }
+
+        for (event_type, event) in &changes.account_data {
+            self.account_data
+                .insert(event_type.to_string(), event.clone());
+        }
+
+        for (room, events) in &changes.room_account_data {
+            for (event_type, event) in events {
+                self.room_account_data
+                    .entry(room.clone())
+                    .or_insert_with(DashMap::new)
+                    .insert(event_type.to_string(), event.clone());
+            }
+        }
+
+        for (room, event_types) in &changes.state {
+            for events in event_types.values() {
+                for event in events.values() {
+                    self.room_state
+                        .entry(room.clone())
+                        .or_insert_with(DashMap::new)
+                        .entry(event.content().event_type().to_string())
+                        .or_insert_with(DashMap::new)
+                        .insert(event.state_key().to_string(), event.clone());
+                }
+            }
+        }
+
+        for (room_id, room_info) in &changes.room_infos {
+            self.room_info.insert(room_id.clone(), room_info.clone());
+        }
+
+        for (sender, event) in &changes.presence {
+            self.presence.insert(sender.clone(), event.clone());
+        }
+
+        for (room_id, info) in &changes.invited_room_info {
+            self.stripped_room_info
+                .insert(room_id.clone(), info.clone());
+        }
+
+        for (room, events) in &changes.stripped_members {
+            for event in events.values() {
+                self.stripped_members
+                    .entry(room.clone())
+                    .or_insert_with(DashMap::new)
+                    .insert(event.state_key.clone(), event.clone());
+            }
+        }
+
+        for (room, event_types) in &changes.stripped_state {
+            for events in event_types.values() {
+                for event in events.values() {
+                    self.stripped_room_state
+                        .entry(room.clone())
+                        .or_insert_with(DashMap::new)
+                        .entry(event.content().event_type().to_string())
+                        .or_insert_with(DashMap::new)
+                        .insert(event.state_key().to_string(), event.clone());
+                }
+            }
+        }
+
+        info!("Saved changes in {:?}", now.elapsed());
+
+        Ok(())
+    }
+
+    pub async fn get_presence_event(&self, user_id: &UserId) -> Result<Option<PresenceEvent>> {
+        #[allow(clippy::map_clone)]
+        Ok(self.presence.get(user_id).map(|p| p.clone()))
+    }
+
+    pub async fn get_state_event(
+        &self,
+        room_id: &RoomId,
+        event_type: EventType,
+        state_key: &str,
+    ) -> Result<Option<AnySyncStateEvent>> {
+        #[allow(clippy::map_clone)]
+        Ok(self.room_state.get(room_id).and_then(|e| {
+            e.get(event_type.as_ref())
+                .and_then(|s| s.get(state_key).map(|e| e.clone()))
+        }))
+    }
+
+    pub async fn get_profile(
+        &self,
+        room_id: &RoomId,
+        user_id: &UserId,
+    ) -> Result<Option<MemberEventContent>> {
+        #[allow(clippy::map_clone)]
+        Ok(self
+            .profiles
+            .get(room_id)
+            .and_then(|p| p.get(user_id).map(|p| p.clone())))
+    }
+
+    pub async fn get_member_event(
+        &self,
+        room_id: &RoomId,
+        state_key: &UserId,
+    ) -> Result<Option<MemberEvent>> {
+        #[allow(clippy::map_clone)]
+        Ok(self
+            .members
+            .get(room_id)
+            .and_then(|m| m.get(state_key).map(|m| m.clone())))
+    }
+
+    fn get_invited_user_ids(&self, room_id: &RoomId) -> Vec<UserId> {
+        #[allow(clippy::map_clone)]
+        self.invited_user_ids
+            .get(room_id)
+            .map(|u| u.iter().map(|u| u.clone()).collect())
+            .unwrap_or_default()
+    }
+
+    fn get_joined_user_ids(&self, room_id: &RoomId) -> Vec<UserId> {
+        #[allow(clippy::map_clone)]
+        self.joined_user_ids
+            .get(room_id)
+            .map(|u| u.iter().map(|u| u.clone()).collect())
+            .unwrap_or_default()
+    }
+
+    fn get_room_infos(&self) -> Vec<RoomInfo> {
+        #[allow(clippy::map_clone)]
+        self.room_info.iter().map(|r| r.clone()).collect()
+    }
+}
+
+#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
+#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
+impl StateStore for MemoryStore {
+    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>> {
+        Ok(self.get_invited_user_ids(room_id))
+    }
+
+    async fn get_joined_user_ids(&self, room_id: &RoomId) -> Result<Vec<UserId>> {
+        Ok(self.get_joined_user_ids(room_id))
+    }
+
+    async fn get_room_infos(&self) -> Result<Vec<RoomInfo>> {
+        Ok(self.get_room_infos())
+    }
+}
diff --git a/matrix_sdk_base/src/store/mod.rs b/matrix_sdk_base/src/store/mod.rs
index 76787a97..3e00052d 100644
--- a/matrix_sdk_base/src/store/mod.rs
+++ b/matrix_sdk_base/src/store/mod.rs
@@ -32,8 +32,10 @@ use crate::{
     InvitedRoom, JoinedRoom, LeftRoom, Room, RoomState, Session,
 };
 
+mod memory_store;
 mod sled_store;
-pub use sled_store::SledStore;
+
+use self::{memory_store::MemoryStore, sled_store::SledStore};
 
 #[derive(Debug, thiserror::Error)]
 pub enum StoreError {
@@ -96,20 +98,19 @@ pub trait StateStore: AsyncTraitDeps {
 #[derive(Debug, Clone)]
 pub struct Store {
     inner: Arc<Box<dyn StateStore>>,
-    session: Arc<RwLock<Option<Session>>>,
-    sync_token: Arc<RwLock<Option<String>>>,
+    pub(crate) session: Arc<RwLock<Option<Session>>>,
+    pub(crate) sync_token: Arc<RwLock<Option<String>>>,
     rooms: Arc<DashMap<RoomId, Room>>,
     stripped_rooms: Arc<DashMap<RoomId, StrippedRoom>>,
 }
 
 impl Store {
-    pub fn new(
-        session: Arc<RwLock<Option<Session>>>,
-        sync_token: Arc<RwLock<Option<String>>>,
-        inner: SledStore,
-    ) -> Self {
+    fn new(inner: Box<dyn StateStore>) -> Self {
+        let session = Arc::new(RwLock::new(None));
+        let sync_token = Arc::new(RwLock::new(None));
+
         Self {
-            inner: Arc::new(Box::new(inner)),
+            inner: inner.into(),
             session,
             sync_token,
             rooms: DashMap::new().into(),
@@ -131,13 +132,26 @@ impl Store {
         Ok(())
     }
 
-    pub fn open_default(path: impl AsRef<Path>) -> Result<Self> {
-        let inner = SledStore::open_with_path(path)?;
-        Ok(Self::new(
-            Arc::new(RwLock::new(None)),
-            Arc::new(RwLock::new(None)),
-            inner,
-        ))
+    pub fn open_memory_store() -> Self {
+        let inner = Box::new(MemoryStore::new());
+
+        Self::new(inner)
+    }
+
+    pub fn open_default(path: impl AsRef<Path>, passphrase: Option<&str>) -> Result<Self> {
+        let inner = if let Some(passphrase) = passphrase {
+            Box::new(SledStore::open_with_passphrase(path, passphrase)?)
+        } else {
+            Box::new(SledStore::open_with_path(path)?)
+        };
+
+        Ok(Self::new(inner))
+    }
+
+    pub fn open_temporrary() -> Result<Self> {
+        let inner = Box::new(SledStore::open()?);
+
+        Ok(Self::new(inner))
     }
 
     pub(crate) fn get_bare_room(&self, room_id: &RoomId) -> Option<Room> {