Index: src/MTXSQLite3Storage.m
==================================================================
--- src/MTXSQLite3Storage.m
+++ src/MTXSQLite3Storage.m
@@ -79,10 +79,15 @@
 	[_conn executeStatement: @"CREATE TABLE IF NOT EXISTS next_batch (\n"
 				 @"    device_id TEXT PRIMARY KEY,\n"
 				 @"    next_batch TEXT\n"
 				 @")"];
 }
+
+- (void)transactionWithBlock: (mtx_storage_transaction_block_t)block
+{
+	[_conn transactionWithBlock: block];
+}
 
 - (void)setNextBatch: (OFString *)nextBatch
 	 forDeviceID: (OFString *)deviceID
 {
 	void *pool = objc_autoreleasePoolPush();

Index: src/MTXStorage.h
==================================================================
--- src/MTXStorage.h
+++ src/MTXStorage.h
@@ -22,14 +22,27 @@
 
 #import <ObjFW/ObjFW.h>
 
 OF_ASSUME_NONNULL_BEGIN
 
+/**
+ * @brief A block which will be treated as a single transaction for the storage.
+ *
+ * @return Whether the transaction should be committed (`true`) or rolled back
+ *	   (`false`).
+ */
+typedef bool (^mtx_storage_transaction_block_t)(void);
+
 /**
  * @brief A protocol for a storage to be used by @ref MTXClient.
  */
 @protocol MTXStorage <OFObject>
+/**
+ * @brief Performs all operations inside the block as a transaction.
+ */
+- (void)transactionWithBlock: (mtx_storage_transaction_block_t)block;
+
 /**
  * @brief Stores the next batch for the specified device.
  *
  * @param nextBatch The next batch for the device
  * @param deviceID The device for which to store the next batch