diff --git a/api_signaling.go b/api_signaling.go
index 5434e500..2edb10aa 100644
--- a/api_signaling.go
+++ b/api_signaling.go
@@ -1053,6 +1053,7 @@ type EventServerMessageSessionEntry struct {
 	UserId        string          `json:"userid"`
 	User          json.RawMessage `json:"user,omitempty"`
 	RoomSessionId string          `json:"roomsessionid,omitempty"`
+	Federated     bool            `json:"federated,omitempty"`
 }
 
 func (e *EventServerMessageSessionEntry) Clone() *EventServerMessageSessionEntry {
@@ -1061,6 +1062,7 @@ func (e *EventServerMessageSessionEntry) Clone() *EventServerMessageSessionEntry
 		UserId:        e.UserId,
 		User:          e.User,
 		RoomSessionId: e.RoomSessionId,
+		Federated:     e.Federated,
 	}
 }
 
diff --git a/docs/standalone-signaling-api-v1.md b/docs/standalone-signaling-api-v1.md
index 2fe9b49d..6646bdc6 100644
--- a/docs/standalone-signaling-api-v1.md
+++ b/docs/standalone-signaling-api-v1.md
@@ -650,6 +650,10 @@ Room event session object:
       }
     }
 
+If a session is federated, an additional entry `"federated": true` will be
+available.
+
+
 Message format (Server -> Client, user(s) left):
 
     {
diff --git a/federation_test.go b/federation_test.go
index ba00fdac..c615e3b5 100644
--- a/federation_test.go
+++ b/federation_test.go
@@ -137,6 +137,7 @@ func Test_Federation(t *testing.T) {
 		remoteSessionId = evt.SessionId
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"2", evt.UserId)
+		assert.True(evt.Federated)
 	}
 
 	// The client2 will see its own session id, not the one from the remote server.
@@ -183,6 +184,7 @@ func Test_Federation(t *testing.T) {
 		remoteSessionId = evt.SessionId
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"2", evt.UserId)
+		assert.True(evt.Federated)
 	}
 	assert.NoError(client2.RunUntilJoined(ctx, hello1.Hello, hello2.Hello))
 
@@ -347,6 +349,7 @@ func Test_Federation(t *testing.T) {
 		remoteSessionId4 = evt.SessionId
 		assert.NotEqual(hello4.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"4", evt.UserId)
+		assert.True(evt.Federated)
 	}
 
 	assert.NoError(client2.RunUntilJoined(ctx, &HelloServerMessage{
@@ -449,6 +452,7 @@ func Test_FederationMedia(t *testing.T) {
 		remoteSessionId = evt.SessionId
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"2", evt.UserId)
+		assert.True(evt.Federated)
 	}
 
 	// The client2 will see its own session id, not the one from the remote server.
@@ -540,6 +544,7 @@ func Test_FederationResume(t *testing.T) {
 		remoteSessionId = evt.SessionId
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"2", evt.UserId)
+		assert.True(evt.Federated)
 	}
 
 	// The client2 will see its own session id, not the one from the remote server.
@@ -667,6 +672,7 @@ func Test_FederationResumeNewSession(t *testing.T) {
 		remoteSessionId = evt.SessionId
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(hello2.Hello.UserId, evt.UserId)
+		assert.True(evt.Federated)
 	}
 
 	// The client2 will see its own session id, not the one from the remote server.
@@ -708,6 +714,7 @@ func Test_FederationResumeNewSession(t *testing.T) {
 		remoteSessionId = evt.SessionId
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(hello2.Hello.UserId, evt.UserId)
+		assert.True(evt.Federated)
 	}
 
 	// client2 will join the room again after the reconnect with the new
diff --git a/room.go b/room.go
index 39ce6bdc..2ef1f890 100644
--- a/room.go
+++ b/room.go
@@ -367,6 +367,7 @@ func (r *Room) notifySessionJoined(sessionId string) {
 		}
 		if s, ok := s.(*ClientSession); ok {
 			entry.RoomSessionId = s.RoomSessionId()
+			entry.Federated = s.ClientType() == HelloClientTypeFederation
 		}
 		events = append(events, entry)
 	}
@@ -535,6 +536,7 @@ func (r *Room) PublishSessionJoined(session Session, sessionData *RoomSessionDat
 	}
 	if session, ok := session.(*ClientSession); ok {
 		message.Event.Join[0].RoomSessionId = session.RoomSessionId()
+		message.Event.Join[0].Federated = session.ClientType() == HelloClientTypeFederation
 	}
 	if err := r.publish(message); err != nil {
 		log.Printf("Could not publish session joined message in room %s: %s", r.Id(), err)