diff --git a/src/MTXClient.h b/src/MTXClient.h
index 7b5dde7..9e2882b 100644
--- a/src/MTXClient.h
+++ b/src/MTXClient.h
@@ -44,6 +44,13 @@ typedef void (^mtx_client_login_block_t)(MTXClient *_Nullable client,
  */
 typedef void (^mtx_client_response_block_t)(id _Nullable exception);
 
+/**
+ * @brief A block called when an exception occurred during sync.
+ *
+ * @param exception The exception which occurred during sync
+ */
+typedef void (^mtx_sync_exception_handler_block_t)(id exception);
+
 /**
  * @brief A block called when the room list was fetched.
  *
@@ -92,6 +99,19 @@ typedef void (^mtx_client_room_join_block_t)(OFString *_Nullable roomID,
  */
 @property (readonly, nonatomic) id <MTXStorage> storage;
 
+/**
+ * @brief The timeout for sync requests.
+ *
+ * Defaults to 5 minutes.
+ */
+@property (nonatomic) of_time_interval_t syncTimeout;
+
+/**
+ * @brief A block to handle exceptions that occurred during sync.
+ */
+@property (copy, nonatomic)
+    mtx_sync_exception_handler_block_t syncExceptionHandler;
+
 /**
  * @brief Creates a new client with the specified access token on the specified
  *	  homeserver.
@@ -143,12 +163,17 @@ typedef void (^mtx_client_room_join_block_t)(OFString *_Nullable roomID,
     OF_DESIGNATED_INITIALIZER;
 
 /**
- * @brief Performs a sync.
- *
- * @param block A block to call when a sync was performed
+ * @brief Starts the sync loop.
  */
-- (void)syncWithTimeout: (of_time_interval_t)timeout
-		  block: (mtx_client_response_block_t)block;
+- (void)startSyncLoop;
+
+/**
+ * @brief Stops the sync loop.
+ *
+ * The currently waiting sync is not aborted, but after it returns, no new sync
+ * will be started.
+ */
+- (void)stopSyncLoop;
 
 /**
  * @brief Logs out the device and invalidates the access token.
diff --git a/src/MTXClient.m b/src/MTXClient.m
index 4f401d2..59cee99 100644
--- a/src/MTXClient.m
+++ b/src/MTXClient.m
@@ -48,6 +48,10 @@ validateHomeserver(OFURL *homeserver)
 }
 
 @implementation MTXClient
+{
+	bool _syncing;
+}
+
 + (instancetype)clientWithUserID: (OFString *)userID
 			deviceID: (OFString *)deviceID
 		     accessToken: (OFString *)accessToken
@@ -158,6 +162,7 @@ validateHomeserver(OFURL *homeserver)
 		_accessToken = [accessToken copy];
 		_homeserver = [homeserver copy];
 		_storage = [storage retain];
+		_syncTimeout = 300;
 	} @catch (id e) {
 		[self release];
 		@throw e;
@@ -196,13 +201,17 @@ validateHomeserver(OFURL *homeserver)
 				homeserver: _homeserver];
 }
 
-- (void)syncWithTimeout: (of_time_interval_t)timeout
-		  block: (mtx_client_response_block_t)block
+- (void)startSyncLoop
 {
+	if (_syncing)
+		return;
+
+	_syncing = true;
+
 	void *pool = objc_autoreleasePoolPush();
 	MTXRequest *request = [self
 	    requestWithPath: @"/_matrix/client/r0/sync"];
-	unsigned long long timeoutMs = timeout * 1000;
+	unsigned long long timeoutMs = _syncTimeout * 1000;
 	OFMutableDictionary<OFString *, OFString *> *query =
 	    [OFMutableDictionary dictionaryWithObject: @(timeoutMs).stringValue
 					       forKey: @"timeout"];
@@ -211,21 +220,25 @@ validateHomeserver(OFURL *homeserver)
 	[request performWithBlock: ^ (mtx_response_t response, int statusCode,
 				       id exception) {
 		if (exception != nil) {
-			block(exception);
+			if (_syncExceptionHandler != NULL)
+				_syncExceptionHandler(exception);
 			return;
 		}
 
 		if (statusCode != 200) {
-			block([MTXSyncFailedException
-			    exceptionWithStatusCode: statusCode
-					   response: response
-					     client: self]);
+			if (_syncExceptionHandler != NULL)
+				_syncExceptionHandler([MTXSyncFailedException
+				    exceptionWithStatusCode: statusCode
+						   response: response
+						     client: self]);
 			return;
 		}
 
 		OFString *nextBatch = response[@"next_batch"];
 		if (![nextBatch isKindOfClass: OFString.class]) {
-			block([OFInvalidServerReplyException exception]);
+			if (_syncExceptionHandler != NULL)
+				_syncExceptionHandler(
+				    [OFInvalidServerReplyException exception]);
 			return;
 		}
 
@@ -245,16 +258,23 @@ validateHomeserver(OFURL *homeserver)
 				return true;
 			}];
 		} @catch (id e) {
-			block(e);
+			if (_syncExceptionHandler != NULL)
+				_syncExceptionHandler(e);
 			return;
 		}
 
-		block(nil);
+		if (_syncing)
+			[self startSyncLoop];
 	}];
 
 	objc_autoreleasePoolPop(pool);
 }
 
+- (void)stopSyncLoop
+{
+	_syncing = false;
+}
+
 - (void)logOutWithBlock: (mtx_client_response_block_t)block
 {
 	void *pool = objc_autoreleasePoolPush();
diff --git a/tests/tests.m b/tests/tests.m
index 7ccd6dd..bdba02d 100644
--- a/tests/tests.m
+++ b/tests/tests.m
@@ -63,21 +63,7 @@ OF_APPLICATION_DELEGATE(Tests)
 		_client = [client retain];
 		of_log(@"Logged in client: %@", _client);
 
-		[self sync];
-	}];
-}
-
-- (void)sync
-{
-	[_client syncWithTimeout: 5
-			   block: ^ (id exception) {
-		if (exception != nil) {
-			of_log(@"Failed to sync: %@", exception);
-			[OFApplication terminateWithStatus: 1];
-		}
-
-		of_log(@"Synced");
-
+		[_client startSyncLoop];
 		[self fetchRoomList];
 	}];
 }
@@ -110,21 +96,6 @@ OF_APPLICATION_DELEGATE(Tests)
 		_roomID = [roomID copy];
 		of_log(@"Joined room %@", _roomID);
 
-		[self sync2];
-	}];
-}
-
-- (void)sync2
-{
-	[_client syncWithTimeout: 5
-			   block: ^ (id exception) {
-		if (exception != nil) {
-			of_log(@"Failed to sync: %@", exception);
-			[OFApplication terminateWithStatus: 1];
-		}
-
-		of_log(@"Synced");
-
 		[self sendMessage];
 	}];
 }
@@ -142,7 +113,11 @@ OF_APPLICATION_DELEGATE(Tests)
 
 		of_log(@"Message sent to %@", _roomID);
 
-		[self leaveRoom];
+		of_log(
+		    @"Waiting 5 seconds before leaving room and logging out");
+
+		[self performSelector: @selector(leaveRoom)
+			   afterDelay: 5];
 	}];
 }