feat: database transaction support (#4414)

Co-authored-by: Joel Solano <solano.joel@gmx.de>

docs/content/docs/adapters/mongo.mdx

@@ -20,7 +20,7 @@ const client = new MongoClient("mongodb://localhost:27017/database");
 const db = client.db();
 
 export const auth = betterAuth({
-  database: mongodbAdapter(db),
+  database: mongodbAdapter(db, { client }),
 });
 ```
 

docs/content/docs/guides/create-a-db-adapter.mdx

@@ -452,6 +452,16 @@ const adapter = myAdapter({
 });
 ```
 
+### `transaction`
+
+Whether the adapter supports transactions. If `false`, operations run sequentially; otherwise provide a function that executes a callback with a `TransactionAdapter`.
+
+<Callout type="warn">
+  If your database does not support transactions, the error handling and rollback
+  will not be as robust. We recommend using a database that supports transactions
+  for better data integrity.
+</Callout>
+
 ### `debugLogs`
 
 Used to enable debug logs for the adapter. You can pass in a boolean, or an object with the following keys: `create`, `update`, `updateMany`, `findOne`, `findMany`, `delete`, `deleteMany`, `count`.

packages/better-auth/src/__snapshots__/init.test.ts.snap

@@ -20,11 +20,13 @@ exports[`init > should match config 1`] = `
         "supportsDates": false,
         "supportsJSON": false,
         "supportsNumericIds": true,
+        "transaction": [Function],
         "usePlural": undefined,
       },
       "debugLogs": false,
       "type": "sqlite",
     },
+    "transaction": [Function],
     "update": [Function],
     "updateMany": [Function],
   },

packages/better-auth/src/adapters/create-adapter/index.ts

@@ -1,13 +1,17 @@
 import { safeJSONParse } from "../../utils/json";
 import { withApplyDefault } from "../../adapters/utils";
 import { getAuthTables } from "../../db/get-tables";
-import type { Adapter, BetterAuthOptions, Where } from "../../types";
+import type {
+	Adapter,
+	BetterAuthOptions,
+	TransactionAdapter,
+	Where,
+} from "../../types";
 import { generateId as defaultGenerateId, logger } from "../../utils";
 import type {
-	AdapterConfig,
+	CreateAdapterOptions,
 	AdapterTestDebugLogs,
 	CleanedWhere,
-	CreateCustomAdapter,
 } from "./types";
 import type { FieldAttribute } from "../../db";
 export * from "./types";
@@ -45,14 +49,13 @@ const colors = {
 	},
 };
 
+const createAsIsTransaction =
+	(adapter: Adapter) =>
+	<R>(fn: (trx: TransactionAdapter) => Promise<R>) =>
+		fn(adapter);
+
 export const createAdapter =
-	({
+	({ adapter: customAdapter, config: cfg }: CreateAdapterOptions) =>
-		adapter,
-		config: cfg,
-	}: {
-		config: AdapterConfig;
-		adapter: CreateCustomAdapter;
-	}) =>
 	(options: BetterAuthOptions): Adapter => {
 		const config = {
 			...cfg,
@@ -315,7 +318,7 @@ export const createAdapter =
 			return fields[defaultFieldName];
 		};
 
-		const adapterInstance = adapter({
+		const adapterInstance = customAdapter({
 			options,
 			schema,
 			debugLog,
@@ -560,7 +563,24 @@ export const createAdapter =
 			}) as any;
 		};
 
-		return {
+		let lazyLoadTransaction: Adapter["transaction"] | null = null;
+		const adapter: Adapter = {
+			transaction: async (cb) => {
+				if (!lazyLoadTransaction) {
+					if (!config.transaction) {
+						logger.warn(
+							`[${config.adapterName}] - Transactions are not supported. Executing operations sequentially.`,
+						);
+						lazyLoadTransaction = createAsIsTransaction(adapter);
+					} else {
+						logger.debug(
+							`[${config.adapterName}] - Using provided transaction implementation.`,
+						);
+						lazyLoadTransaction = config.transaction;
+					}
+				}
+				return lazyLoadTransaction(cb);
+			},
 			create: async <T extends Record<string, any>, R = T>({
 				data: unsafeData,
 				model: unsafeModel,
@@ -1016,6 +1036,7 @@ export const createAdapter =
 					}
 				: {}),
 		};
+		return adapter;
 	};
 
 function formatTransactionId(transactionId: number) {

packages/better-auth/src/adapters/create-adapter/types.ts

@@ -3,6 +3,7 @@ import type { BetterAuthDbSchema } from "../../db/get-tables";
 import type {
 	AdapterSchemaCreation,
 	BetterAuthOptions,
+	TransactionAdapter,
 	Where,
 } from "../../types";
 import type { Prettify } from "../../types/helper";
@@ -32,6 +33,11 @@ export type AdapterDebugLogs =
 			isRunningAdapterTests: boolean;
 	  };
 
+export type CreateAdapterOptions = {
+	config: AdapterConfig;
+	adapter: CreateCustomAdapter;
+};
+
 export interface AdapterConfig {
 	/**
 	 * Use plural table names.
@@ -89,6 +95,15 @@ export interface AdapterConfig {
 	 * @default true
 	 */
 	supportsBooleans?: boolean;
+	/**
+	 * Execute multiple operations in a transaction.
+	 *
+	 * If the database doesn't support transactions, set this to `false` and operations will be executed sequentially.
+	 *
+	 */
+	transaction?:
+		| false
+		| (<R>(callback: (trx: TransactionAdapter) => Promise<R>) => Promise<R>);
 	/**
 	 * Disable id generation for the `create` method.
 	 *

packages/better-auth/src/adapters/drizzle-adapter/drizzle-adapter.ts

@@ -17,8 +17,13 @@ import {
 	SQL,
 } from "drizzle-orm";
 import { BetterAuthError } from "../../error";
-import type { Where } from "../../types";
+import type { Adapter, BetterAuthOptions, Where } from "../../types";
-import { createAdapter, type AdapterDebugLogs } from "../create-adapter";
+import {
+	createAdapter,
+	type AdapterDebugLogs,
+	type CreateAdapterOptions,
+	type CreateCustomAdapter,
+} from "../create-adapter";
 
 export interface DB {
 	[key: string]: any;
@@ -52,17 +57,21 @@ export interface DrizzleAdapterConfig {
 	 * @default false
 	 */
 	camelCase?: boolean;
+	/**
+	 * Whether to execute multiple operations in a transaction.
+	 *
+	 * If the database doesn't support transactions,
+	 * set this to `false` and operations will be executed sequentially.
+	 * @default true
+	 */
+	transaction?: boolean;
 }
 
-export const drizzleAdapter = (db: DB, config: DrizzleAdapterConfig) =>
+export const drizzleAdapter = (db: DB, config: DrizzleAdapterConfig) => {
-	createAdapter({
+	let lazyOptions: BetterAuthOptions | null = null;
-		config: {
+	const createCustomAdapter =
-			adapterId: "drizzle",
+		(db: DB): CreateCustomAdapter =>
-			adapterName: "Drizzle Adapter",
+		({ getFieldName, debugLog }) => {
-			usePlural: config.usePlural ?? false,
-			debugLogs: config.debugLogs ?? false,
-		},
-		adapter: ({ getFieldName, debugLog }) => {
 			function getSchema(model: string) {
 				const schema = config.schema || db._.fullSchema;
 				if (!schema) {
@@ -343,5 +352,31 @@ export const drizzleAdapter = (db: DB, config: DrizzleAdapterConfig) =>
 				},
 				options: config,
 			};
+		};
+	let adapterOptions: CreateAdapterOptions | null = null;
+	adapterOptions = {
+		config: {
+			adapterId: "drizzle",
+			adapterName: "Drizzle Adapter",
+			usePlural: config.usePlural ?? false,
+			debugLogs: config.debugLogs ?? false,
+			transaction:
+				(config.transaction ?? true)
+					? (cb) =>
+							db.transaction((tx: DB) => {
+								const adapter = createAdapter({
+									config: adapterOptions!.config,
+									adapter: createCustomAdapter(tx),
+								})(lazyOptions!);
+								return cb(adapter);
+							})
+					: false,
 		},
-	});
+		adapter: createCustomAdapter(db),
+	};
+	const adapter = createAdapter(adapterOptions);
+	return (options: BetterAuthOptions): Adapter => {
+		lazyOptions = options;
+		return adapter(options);
+	};
+};

packages/better-auth/src/adapters/kysely-adapter/kysely-adapter.ts

@@ -1,5 +1,10 @@
-import { createAdapter, type AdapterDebugLogs } from "../create-adapter";
+import {
-import type { Where } from "../../types";
+	createAdapter,
+	type AdapterDebugLogs,
+	type CreateCustomAdapter,
+	type CreateAdapterOptions,
+} from "../create-adapter";
+import type { Adapter, BetterAuthOptions, Where } from "../../types";
 import type { KyselyDatabaseType } from "./types";
 import type { InsertQueryBuilder, Kysely, UpdateQueryBuilder } from "kysely";
 
@@ -20,26 +25,23 @@ interface KyselyAdapterConfig {
 	 * @default false
 	 */
 	usePlural?: boolean;
+	/**
+	 * Whether to execute multiple operations in a transaction.
+	 *
+	 * If the database doesn't support transactions,
+	 * set this to `false` and operations will be executed sequentially.
+	 * @default true
+	 */
+	transaction?: boolean;
 }
 
-export const kyselyAdapter = (db: Kysely<any>, config?: KyselyAdapterConfig) =>
+export const kyselyAdapter = (
-	createAdapter({
+	db: Kysely<any>,
-		config: {
+	config?: KyselyAdapterConfig,
-			adapterId: "kysely",
+) => {
-			adapterName: "Kysely Adapter",
+	let lazyOptions: BetterAuthOptions | null = null;
-			usePlural: config?.usePlural,
+	const createCustomAdapter = (db: Kysely<any>): CreateCustomAdapter => {
-			debugLogs: config?.debugLogs,
+		return ({ getFieldName, schema }) => {
-			supportsBooleans:
-				config?.type === "sqlite" || config?.type === "mssql" || !config?.type
-					? false
-					: true,
-			supportsDates:
-				config?.type === "sqlite" || config?.type === "mssql" || !config?.type
-					? false
-					: true,
-			supportsJSON: false,
-		},
-		adapter: ({ getFieldName, schema }) => {
 			const withReturning = async (
 				values: Record<string, any>,
 				builder:
@@ -315,5 +317,43 @@ export const kyselyAdapter = (db: Kysely<any>, config?: KyselyAdapterConfig) =>
 				},
 				options: config,
 			};
+		};
+	};
+	let adapterOptions: CreateAdapterOptions | null = null;
+	adapterOptions = {
+		config: {
+			adapterId: "kysely",
+			adapterName: "Kysely Adapter",
+			usePlural: config?.usePlural,
+			debugLogs: config?.debugLogs,
+			supportsBooleans:
+				config?.type === "sqlite" || config?.type === "mssql" || !config?.type
+					? false
+					: true,
+			supportsDates:
+				config?.type === "sqlite" || config?.type === "mssql" || !config?.type
+					? false
+					: true,
+			supportsJSON: false,
+			transaction:
+				(config?.transaction ?? true)
+					? (cb) =>
+							db.transaction().execute((trx) => {
+								const adapter = createAdapter({
+									config: adapterOptions!.config,
+									adapter: createCustomAdapter(trx),
+								})(lazyOptions!);
+								return cb(adapter);
+							})
+					: false,
 		},
-	});
+		adapter: createCustomAdapter(db),
+	};
+
+	const adapter = createAdapter(adapterOptions);
+
+	return (options: BetterAuthOptions): Adapter => {
+		lazyOptions = options;
+		return adapter(options);
+	};
+};

packages/better-auth/src/adapters/memory-adapter/adapter.memory.test.ts

@@ -24,6 +24,10 @@ describe("adapter test", async () => {
 				...customOptions,
 			});
 		},
+		disableTests: {
+			SHOULD_ROLLBACK_FAILING_TRANSACTION: true,
+			SHOULD_RETURN_TRANSACTION_RESULT: true,
+		},
 	});
 });
 

packages/better-auth/src/adapters/memory-adapter/memory-adapter.ts

@@ -4,6 +4,7 @@ import {
 	type AdapterDebugLogs,
 	type CleanedWhere,
 } from "../create-adapter";
+import type { BetterAuthOptions } from "../../types";
 
 export interface MemoryDB {
 	[key: string]: any[];
@@ -13,8 +14,9 @@ export interface MemoryAdapterConfig {
 	debugLogs?: AdapterDebugLogs;
 }
 
-export const memoryAdapter = (db: MemoryDB, config?: MemoryAdapterConfig) =>
+export const memoryAdapter = (db: MemoryDB, config?: MemoryAdapterConfig) => {
-	createAdapter({
+	let lazyOptions: BetterAuthOptions | null = null;
+	let adapterCreator = createAdapter({
 		config: {
 			adapterId: "memory",
 			adapterName: "Memory Adapter",
@@ -30,6 +32,18 @@ export const memoryAdapter = (db: MemoryDB, config?: MemoryAdapterConfig) =>
 				}
 				return props.data;
 			},
+			transaction: async (cb) => {
+				let clone = structuredClone(db);
+				try {
+					return cb(adapterCreator(lazyOptions!));
+				} catch {
+					// Rollback changes
+					Object.keys(db).forEach((key) => {
+						db[key] = clone[key];
+					});
+					throw new Error("Transaction failed, rolling back changes");
+				}
+			},
 		},
 		adapter: ({ getFieldName, options, debugLog }) => {
 			function convertWhereClause(where: CleanedWhere[], model: string) {
@@ -147,3 +161,8 @@ export const memoryAdapter = (db: MemoryDB, config?: MemoryAdapterConfig) =>
 			};
 		},
 	});
+	return (options: BetterAuthOptions) => {
+		lazyOptions = options;
+		return adapterCreator(options);
+	};
+};

packages/better-auth/src/adapters/mongodb-adapter/adapter.mongo-db.test.ts

@@ -9,11 +9,14 @@ describe("adapter test", async () => {
 		const client = new MongoClient(connectionString);
 		await client.connect();
 		const db = client.db(dbName);
-		return db;
+		return { db, client };
 	};
 
 	const user = "user";
-	const db = await dbClient("mongodb://127.0.0.1:27017", "better-auth");
+	const { db, client } = await dbClient(
+		"mongodb://127.0.0.1:27017",
+		"better-auth",
+	);
 	async function clearDb() {
 		await db.collection(user).deleteMany({});
 		await db.collection("session").deleteMany({});
@@ -23,7 +26,10 @@ describe("adapter test", async () => {
 		await clearDb();
 	});
 
-	const adapter = mongodbAdapter(db);
+	const adapter = mongodbAdapter(db, {
+		// MongoDB transactions require a replica set or a sharded cluster
+		// client,
+	});
 	await runAdapterTest({
 		getAdapter: async (customOptions = {}) => {
 			return adapter({
@@ -46,6 +52,8 @@ describe("adapter test", async () => {
 		},
 		disableTests: {
 			SHOULD_PREFER_GENERATE_ID_IF_PROVIDED: true,
+			SHOULD_RETURN_TRANSACTION_RESULT: true,
+			SHOULD_ROLLBACK_FAILING_TRANSACTION: true,
 		},
 	});
 });

packages/better-auth/src/adapters/mongodb-adapter/mongodb-adapter.ts

@@ -1,8 +1,18 @@
-import { ObjectId, type Db } from "mongodb";
+import { ClientSession, ObjectId, type Db, type MongoClient } from "mongodb";
-import type { BetterAuthOptions, Where } from "../../types";
+import type { Adapter, BetterAuthOptions, Where } from "../../types";
-import { createAdapter, type AdapterDebugLogs } from "../create-adapter";
+import {
+	createAdapter,
+	type AdapterDebugLogs,
+	type CreateAdapterOptions,
+	type CreateCustomAdapter,
+} from "../create-adapter";
 
 export interface MongoDBAdapterConfig {
+	/**
+	 * MongoDB Client used for transactions.
+	 * If not provided, operations will be executed without a session.
+	 */
+	client?: MongoClient;
 	/**
 	 * Enable debug logs for the adapter
 	 *
@@ -15,9 +25,18 @@ export interface MongoDBAdapterConfig {
 	 * @default false
 	 */
 	usePlural?: boolean;
+	/**
+	 * Whether to execute multiple operations in a transaction.
+	 *
+	 * If the database doesn't support transactions,
+	 * set this to `false` and operations will be executed sequentially.
+	 * @default true
+	 */
+	transaction?: boolean;
 }
 
 export const mongodbAdapter = (db: Db, config?: MongoDBAdapterConfig) => {
+	let lazyOptions: BetterAuthOptions | null;
 	const getCustomIdGenerator = (options: BetterAuthOptions) => {
 		const generator =
 			options.advanced?.database?.generateId || options.advanced?.generateId;
@@ -26,70 +45,10 @@ export const mongodbAdapter = (db: Db, config?: MongoDBAdapterConfig) => {
 		}
 		return undefined;
 	};
-	return createAdapter({
-		config: {
-			adapterId: "mongodb-adapter",
-			adapterName: "MongoDB Adapter",
-			usePlural: config?.usePlural ?? false,
-			debugLogs: config?.debugLogs ?? false,
-			mapKeysTransformInput: {
-				id: "_id",
-			},
-			mapKeysTransformOutput: {
-				_id: "id",
-			},
-			supportsNumericIds: false,
-			customTransformInput({
-				action,
-				data,
-				field,
-				fieldAttributes,
-				schema,
-				model,
-				options,
-			}) {
-				const customIdGen = getCustomIdGenerator(options);
 
-				if (field === "_id" || fieldAttributes.references?.field === "id") {
+	const createCustomAdapter =
-					if (customIdGen) {
+		(db: Db, session?: ClientSession): CreateCustomAdapter =>
-						return data;
+		({ options, getFieldName, schema, getDefaultModelName }) => {
-					}
-					if (action === "update") {
-						return data;
-					}
-					if (Array.isArray(data)) {
-						return data.map((v) => new ObjectId());
-					}
-					if (typeof data === "string") {
-						try {
-							return new ObjectId(data);
-						} catch (error) {
-							return new ObjectId();
-						}
-					}
-					return new ObjectId();
-				}
-				return data;
-			},
-			customTransformOutput({ data, field, fieldAttributes }) {
-				if (field === "id" || fieldAttributes.references?.field === "id") {
-					if (data instanceof ObjectId) {
-						return data.toHexString();
-					}
-					if (Array.isArray(data)) {
-						return data.map((v) => {
-							if (v instanceof ObjectId) {
-								return v.toHexString();
-							}
-							return v;
-						});
-					}
-					return data;
-				}
-				return data;
-			},
-		},
-		adapter: ({ options, getFieldName, schema, getDefaultModelName }) => {
 			const customIdGen = getCustomIdGenerator(options);
 
 			function serializeID({
@@ -238,19 +197,19 @@ export const mongodbAdapter = (db: Db, config?: MongoDBAdapterConfig) => {
 
 			return {
 				async create({ model, data: values }) {
-					const res = await db.collection(model).insertOne(values);
+					const res = await db.collection(model).insertOne(values, { session });
 					const insertedData = { _id: res.insertedId.toString(), ...values };
 					return insertedData as any;
 				},
 				async findOne({ model, where, select }) {
 					const clause = convertWhereClause({ where, model });
-					const res = await db.collection(model).findOne(clause);
+					const res = await db.collection(model).findOne(clause, { session });
 					if (!res) return null;
 					return res as any;
 				},
 				async findMany({ model, where, limit, offset, sortBy }) {
 					const clause = where ? convertWhereClause({ where, model }) : {};
-					const cursor = db.collection(model).find(clause);
+					const cursor = db.collection(model).find(clause, { session });
 					if (limit) cursor.limit(limit);
 					if (offset) cursor.skip(offset);
 					if (sortBy)
@@ -262,7 +221,9 @@ export const mongodbAdapter = (db: Db, config?: MongoDBAdapterConfig) => {
 					return res as any;
 				},
 				async count({ model }) {
-					const res = await db.collection(model).countDocuments();
+					const res = await db
+						.collection(model)
+						.countDocuments(undefined, { session });
 					return res;
 				},
 				async update({ model, where, update: values }) {
@@ -272,6 +233,7 @@ export const mongodbAdapter = (db: Db, config?: MongoDBAdapterConfig) => {
 						clause,
 						{ $set: values as any },
 						{
+							session,
 							returnDocument: "after",
 						},
 					);
@@ -281,21 +243,129 @@ export const mongodbAdapter = (db: Db, config?: MongoDBAdapterConfig) => {
 				async updateMany({ model, where, update: values }) {
 					const clause = convertWhereClause({ where, model });
 
-					const res = await db.collection(model).updateMany(clause, {
+					const res = await db.collection(model).updateMany(
+						clause,
+						{
 							$set: values as any,
-					});
+						},
+						{ session },
+					);
 					return res.modifiedCount;
 				},
 				async delete({ model, where }) {
 					const clause = convertWhereClause({ where, model });
-					await db.collection(model).deleteOne(clause);
+					await db.collection(model).deleteOne(clause, { session });
 				},
 				async deleteMany({ model, where }) {
 					const clause = convertWhereClause({ where, model });
-					const res = await db.collection(model).deleteMany(clause);
+					const res = await db
+						.collection(model)
+						.deleteMany(clause, { session });
 					return res.deletedCount;
 				},
 			};
-		},
+		};
-	});
+
+	let lazyAdapter: ((options: BetterAuthOptions) => Adapter) | null = null;
+	let adapterOptions: CreateAdapterOptions | null = null;
+	adapterOptions = {
+		config: {
+			adapterId: "mongodb-adapter",
+			adapterName: "MongoDB Adapter",
+			usePlural: config?.usePlural ?? false,
+			debugLogs: config?.debugLogs ?? false,
+			mapKeysTransformInput: {
+				id: "_id",
+			},
+			mapKeysTransformOutput: {
+				_id: "id",
+			},
+			supportsNumericIds: false,
+			transaction:
+				config?.client && (config?.transaction ?? true)
+					? async (cb) => {
+							if (!config.client) {
+								return cb(lazyAdapter!(lazyOptions!));
+							}
+
+							const session = config.client.startSession();
+
+							try {
+								session.startTransaction();
+
+								const adapter = createAdapter({
+									config: adapterOptions!.config,
+									adapter: createCustomAdapter(db, session),
+								})(lazyOptions!);
+
+								const result = await cb(adapter);
+
+								await session.commitTransaction();
+								return result;
+							} catch (err) {
+								await session.abortTransaction();
+								throw err;
+							} finally {
+								await session.endSession();
+							}
+						}
+					: false,
+			customTransformInput({
+				action,
+				data,
+				field,
+				fieldAttributes,
+				schema,
+				model,
+				options,
+			}) {
+				const customIdGen = getCustomIdGenerator(options);
+
+				if (field === "_id" || fieldAttributes.references?.field === "id") {
+					if (customIdGen) {
+						return data;
+					}
+					if (action === "update") {
+						return data;
+					}
+					if (Array.isArray(data)) {
+						return data.map((v) => new ObjectId());
+					}
+					if (typeof data === "string") {
+						try {
+							return new ObjectId(data);
+						} catch (error) {
+							return new ObjectId();
+						}
+					}
+					return new ObjectId();
+				}
+				return data;
+			},
+			customTransformOutput({ data, field, fieldAttributes }) {
+				if (field === "id" || fieldAttributes.references?.field === "id") {
+					if (data instanceof ObjectId) {
+						return data.toHexString();
+					}
+					if (Array.isArray(data)) {
+						return data.map((v) => {
+							if (v instanceof ObjectId) {
+								return v.toHexString();
+							}
+							return v;
+						});
+					}
+					return data;
+				}
+				return data;
+			},
+		},
+		adapter: createCustomAdapter(db),
+	};
+	lazyAdapter = createAdapter(adapterOptions);
+
+	return (options: BetterAuthOptions): Adapter => {
+		lazyOptions = options;
+		return lazyAdapter(options);
+	};
 };

packages/better-auth/src/adapters/prisma-adapter/prisma-adapter.ts

@@ -1,6 +1,11 @@
 import { BetterAuthError } from "../../error";
-import type { Where } from "../../types";
+import type { Adapter, BetterAuthOptions, Where } from "../../types";
-import { createAdapter, type AdapterDebugLogs } from "../create-adapter";
+import {
+	createAdapter,
+	type AdapterDebugLogs,
+	type CreateAdapterOptions,
+	type CreateCustomAdapter,
+} from "../create-adapter";
 
 export interface PrismaConfig {
 	/**
@@ -27,11 +32,24 @@ export interface PrismaConfig {
 	 * @default false
 	 */
 	usePlural?: boolean;
+
+	/**
+	 * Whether to execute multiple operations in a transaction.
+	 *
+	 * If the database doesn't support transactions,
+	 * set this to `false` and operations will be executed sequentially.
+	 * @default true
+	 */
+	transaction?: boolean;
 }
 
 interface PrismaClient {}
 
-interface PrismaClientInternal {
+type PrismaClientInternal = {
+	$transaction: (
+		callback: (db: PrismaClient) => Promise<any> | any,
+	) => Promise<any>;
+} & {
 	[model: string]: {
 		create: (data: any) => Promise<any>;
 		findFirst: (data: any) => Promise<any>;
@@ -40,17 +58,13 @@ interface PrismaClientInternal {
 		delete: (data: any) => Promise<any>;
 		[key: string]: any;
 	};
-}
+};
 
-export const prismaAdapter = (prisma: PrismaClient, config: PrismaConfig) =>
+export const prismaAdapter = (prisma: PrismaClient, config: PrismaConfig) => {
-	createAdapter({
+	let lazyOptions: BetterAuthOptions | null = null;
-		config: {
+	const createCustomAdapter =
-			adapterId: "prisma",
+		(prisma: PrismaClient): CreateCustomAdapter =>
-			adapterName: "Prisma Adapter",
+		({ getFieldName }) => {
-			usePlural: config.usePlural ?? false,
-			debugLogs: config.debugLogs ?? false,
-		},
-		adapter: ({ getFieldName }) => {
 			const db = prisma as PrismaClientInternal;
 
 			const convertSelect = (select?: string[], model?: string) => {
@@ -217,5 +231,33 @@ export const prismaAdapter = (prisma: PrismaClient, config: PrismaConfig) =>
 				},
 				options: config,
 			};
+		};
+
+	let adapterOptions: CreateAdapterOptions | null = null;
+	adapterOptions = {
+		config: {
+			adapterId: "prisma",
+			adapterName: "Prisma Adapter",
+			usePlural: config.usePlural ?? false,
+			debugLogs: config.debugLogs ?? false,
+			transaction:
+				(config.transaction ?? true)
+					? (cb) =>
+							(prisma as PrismaClientInternal).$transaction((tx) => {
+								const adapter = createAdapter({
+									config: adapterOptions!.config,
+									adapter: createCustomAdapter(tx),
+								})(lazyOptions!);
+								return cb(adapter);
+							})
+					: false,
 		},
-	});
+		adapter: createCustomAdapter(prisma),
+	};
+
+	const adapter = createAdapter(adapterOptions);
+	return (options: BetterAuthOptions): Adapter => {
+		lazyOptions = options;
+		return adapter(options);
+	};
+};

packages/better-auth/src/adapters/test.ts

@@ -47,6 +47,8 @@ const adapterTests = {
 	SHOULD_SEARCH_USERS_WITH_STARTS_WITH: "should search users with startsWith",
 	SHOULD_SEARCH_USERS_WITH_ENDS_WITH: "should search users with endsWith",
 	SHOULD_PREFER_GENERATE_ID_IF_PROVIDED: "should prefer generateId if provided",
+	SHOULD_ROLLBACK_FAILING_TRANSACTION: "should rollback failing transaction",
+	SHOULD_RETURN_TRANSACTION_RESULT: "should return transaction result",
 } as const;
 
 const { ...numberIdAdapterTestsCopy } = adapterTests;
@@ -820,6 +822,83 @@ async function adapterTest(
 			expect(res.id).toBe("mocked-id");
 		},
 	);
+
+	test.skipIf(disabledTests?.SHOULD_ROLLBACK_FAILING_TRANSACTION)(
+		`${testPrefix ? `${testPrefix} - ` : ""}${adapterTests.SHOULD_ROLLBACK_FAILING_TRANSACTION}`,
+		async ({ onTestFailed }) => {
+			await resetDebugLogs();
+			onTestFailed(async () => {
+				await printDebugLogs();
+			});
+			const customAdapter = await adapter();
+			const user5 = {
+				name: "user5",
+				email: "user5@email.com",
+				emailVerified: true,
+				createdAt: new Date(),
+				updatedAt: new Date(),
+			};
+			const user6 = {
+				name: "user6",
+				email: "user6@email.com",
+				emailVerified: true,
+				createdAt: new Date(),
+				updatedAt: new Date(),
+			};
+			await expect(
+				customAdapter.transaction(async (tx) => {
+					await tx.create({ model: "user", data: user5 });
+					throw new Error("Simulated failure");
+					await tx.create({ model: "user", data: user6 });
+				}),
+			).rejects.toThrow("Simulated failure");
+
+			await expect(
+				customAdapter.findMany({
+					model: "user",
+					where: [
+						{
+							field: "email",
+							value: user5.email,
+							connector: "OR",
+						},
+						{
+							field: "email",
+							value: user6.email,
+							connector: "OR",
+						},
+					],
+				}),
+			).resolves.toEqual([]);
+		},
+	);
+
+	test.skipIf(disabledTests?.SHOULD_RETURN_TRANSACTION_RESULT)(
+		`${testPrefix ? `${testPrefix} - ` : ""}${adapterTests.SHOULD_RETURN_TRANSACTION_RESULT}`,
+		async ({ onTestFailed }) => {
+			await resetDebugLogs();
+			onTestFailed(async () => {
+				await printDebugLogs();
+			});
+			const customAdapter = await adapter();
+			const result = await customAdapter.transaction(async (tx) => {
+				const createdUser = await tx.create<User>({
+					model: "user",
+					data: {
+						name: "user6",
+						email: "user6@email.com",
+						emailVerified: true,
+						createdAt: new Date(),
+						updatedAt: new Date(),
+					},
+				});
+
+				return createdUser.email;
+			});
+
+			expect(result).toEqual("user6@email.com");
+		},
+	);
 }
 
 export async function runAdapterTest(opts: AdapterTestOptions) {

packages/better-auth/src/db/internal-adapter.ts

@@ -5,6 +5,7 @@ import type {
 	AuthContext,
 	BetterAuthOptions,
 	GenericEndpointContext,
+	TransactionAdapter,
 	Where,
 } from "../types";
 import {
@@ -41,6 +42,7 @@ export const createInternalAdapter = (
 				Partial<Account>,
 			context?: GenericEndpointContext,
 		) => {
+			return adapter.transaction(async (trxAdapter) => {
 				const createdUser = await createWithHooks(
 					{
 						// todo: we should remove auto setting createdAt and updatedAt in the next major release, since the db generators already handle that
@@ -51,6 +53,7 @@ export const createInternalAdapter = (
 					"user",
 					undefined,
 					context,
+					trxAdapter,
 				);
 				const createdAccount = await createWithHooks(
 					{
@@ -63,17 +66,20 @@ export const createInternalAdapter = (
 					"account",
 					undefined,
 					context,
+					trxAdapter,
 				);
 				return {
 					user: createdUser,
 					account: createdAccount,
 				};
+			});
 		},
 		createUser: async <T>(
 			user: Omit<User, "id" | "createdAt" | "updatedAt" | "emailVerified"> &
 				Partial<User> &
 				Record<string, any>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const createdUser = await createWithHooks(
 				{
@@ -86,6 +92,7 @@ export const createInternalAdapter = (
 				"user",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return createdUser as T & User;
 		},
@@ -94,6 +101,7 @@ export const createInternalAdapter = (
 				Partial<Account> &
 				T,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const createdAccount = await createWithHooks(
 				{
@@ -105,10 +113,11 @@ export const createInternalAdapter = (
 				"account",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return createdAccount as T & Account;
 		},
-		listSessions: async (userId: string) => {
+		listSessions: async (userId: string, trxAdapter?: TransactionAdapter) => {
 			if (secondaryStorage) {
 				const currentList = await secondaryStorage.get(
 					`active-sessions-${userId}`,
@@ -140,7 +149,7 @@ export const createInternalAdapter = (
 				return sessions;
 			}
 
-			const sessions = await adapter.findMany<Session>({
+			const sessions = await (trxAdapter || adapter).findMany<Session>({
 				model: "session",
 				where: [
 					{
@@ -159,8 +168,9 @@ export const createInternalAdapter = (
 				direction: "asc" | "desc";
 			},
 			where?: Where[],
+			trxAdapter?: TransactionAdapter,
 		) => {
-			const users = await adapter.findMany<User>({
+			const users = await (trxAdapter || adapter).findMany<User>({
 				model: "user",
 				limit,
 				offset,
@@ -169,8 +179,11 @@ export const createInternalAdapter = (
 			});
 			return users;
 		},
-		countTotalUsers: async (where?: Where[]) => {
+		countTotalUsers: async (
-			const total = await adapter.count({
+			where?: Where[],
+			trxAdapter?: TransactionAdapter,
+		) => {
+			const total = await (trxAdapter || adapter).count({
 				model: "user",
 				where,
 			});
@@ -179,13 +192,13 @@ export const createInternalAdapter = (
 			}
 			return total;
 		},
-		deleteUser: async (userId: string) => {
+		deleteUser: async (userId: string, trxAdapter?: TransactionAdapter) => {
 			if (secondaryStorage) {
 				await secondaryStorage.delete(`active-sessions-${userId}`);
 			}
 
 			if (!secondaryStorage || options.session?.storeSessionInDatabase) {
-				await adapter.deleteMany({
+				await (trxAdapter || adapter).deleteMany({
 					model: "session",
 					where: [
 						{
@@ -196,7 +209,7 @@ export const createInternalAdapter = (
 				});
 			}
 
-			await adapter.deleteMany({
+			await (trxAdapter || adapter).deleteMany({
 				model: "account",
 				where: [
 					{
@@ -205,7 +218,7 @@ export const createInternalAdapter = (
 					},
 				],
 			});
-			await adapter.delete({
+			await (trxAdapter || adapter).delete({
 				model: "user",
 				where: [
 					{
@@ -221,6 +234,7 @@ export const createInternalAdapter = (
 			dontRememberMe?: boolean,
 			override?: Partial<Session> & Record<string, any>,
 			overrideAll?: boolean,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const headers = ctx.headers || ctx.request?.headers;
 			const { id: _, ...rest } = override || {};
@@ -285,11 +299,13 @@ export const createInternalAdapter = (
 						}
 					: undefined,
 				ctx,
+				trxAdapter,
 			);
 			return res as Session;
 		},
 		findSession: async (
 			token: string,
+			trxAdapter?: TransactionAdapter,
 		): Promise<{
 			session: Session & Record<string, any>;
 			user: User & Record<string, any>;
@@ -323,7 +339,7 @@ export const createInternalAdapter = (
 				}
 			}
 
-			const session = await adapter.findOne<Session>({
+			const session = await (trxAdapter || adapter).findOne<Session>({
 				model: "session",
 				where: [
 					{
@@ -337,7 +353,7 @@ export const createInternalAdapter = (
 				return null;
 			}
 
-			const user = await adapter.findOne<User>({
+			const user = await (trxAdapter || adapter).findOne<User>({
 				model: "user",
 				where: [
 					{
@@ -357,7 +373,10 @@ export const createInternalAdapter = (
 				user: parsedUser,
 			};
 		},
-		findSessions: async (sessionTokens: string[]) => {
+		findSessions: async (
+			sessionTokens: string[],
+			trxAdapter?: TransactionAdapter,
+		) => {
 			if (secondaryStorage) {
 				const sessions: {
 					session: Session;
@@ -391,7 +410,7 @@ export const createInternalAdapter = (
 				return sessions;
 			}
 
-			const sessions = await adapter.findMany<Session>({
+			const sessions = await (trxAdapter || adapter).findMany<Session>({
 				model: "session",
 				where: [
 					{
@@ -405,7 +424,7 @@ export const createInternalAdapter = (
 				return session.userId;
 			});
 			if (!userIds.length) return [];
-			const users = await adapter.findMany<User>({
+			const users = await (trxAdapter || adapter).findMany<User>({
 				model: "user",
 				where: [
 					{
@@ -431,6 +450,7 @@ export const createInternalAdapter = (
 			sessionToken: string,
 			session: Partial<Session> & Record<string, any>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const updatedSession = await updateWithHooks<Session>(
 				session,
@@ -460,10 +480,11 @@ export const createInternalAdapter = (
 						}
 					: undefined,
 				context,
+				trxAdapter,
 			);
 			return updatedSession;
 		},
-		deleteSession: async (token: string) => {
+		deleteSession: async (token: string, trxAdapter?: TransactionAdapter) => {
 			if (secondaryStorage) {
 				// remove the session from the active sessions list
 				const data = await secondaryStorage.get(token);
@@ -510,7 +531,7 @@ export const createInternalAdapter = (
 					return;
 				}
 			}
-			await adapter.delete<Session>({
+			await (trxAdapter || adapter).delete<Session>({
 				model: "session",
 				where: [
 					{
@@ -520,8 +541,8 @@ export const createInternalAdapter = (
 				],
 			});
 		},
-		deleteAccounts: async (userId: string) => {
+		deleteAccounts: async (userId: string, trxAdapter?: TransactionAdapter) => {
-			await adapter.deleteMany({
+			await (trxAdapter || adapter).deleteMany({
 				model: "account",
 				where: [
 					{
@@ -531,8 +552,11 @@ export const createInternalAdapter = (
 				],
 			});
 		},
-		deleteAccount: async (accountId: string) => {
+		deleteAccount: async (
-			await adapter.delete({
+			accountId: string,
+			trxAdapter?: TransactionAdapter,
+		) => {
+			await (trxAdapter || adapter).delete({
 				model: "account",
 				where: [
 					{
@@ -542,7 +566,10 @@ export const createInternalAdapter = (
 				],
 			});
 		},
-		deleteSessions: async (userIdOrSessionTokens: string | string[]) => {
+		deleteSessions: async (
+			userIdOrSessionTokens: string | string[],
+			trxAdapter?: TransactionAdapter,
+		) => {
 			if (secondaryStorage) {
 				if (typeof userIdOrSessionTokens === "string") {
 					const activeSession = await secondaryStorage.get(
@@ -571,7 +598,7 @@ export const createInternalAdapter = (
 					return;
 				}
 			}
-			await adapter.deleteMany({
+			await (trxAdapter || adapter).deleteMany({
 				model: "session",
 				where: [
 					{
@@ -586,9 +613,10 @@ export const createInternalAdapter = (
 			email: string,
 			accountId: string,
 			providerId: string,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			// we need to find account first to avoid missing user if the email changed with the provider for the same account
-			const account = await adapter
+			const account = await (trxAdapter || adapter)
 				.findMany<Account>({
 					model: "account",
 					where: [
@@ -602,7 +630,7 @@ export const createInternalAdapter = (
 					return accounts.find((a) => a.providerId === providerId);
 				});
 			if (account) {
-				const user = await adapter.findOne<User>({
+				const user = await (trxAdapter || adapter).findOne<User>({
 					model: "user",
 					where: [
 						{
@@ -617,7 +645,7 @@ export const createInternalAdapter = (
 						accounts: [account],
 					};
 				} else {
-					const user = await adapter.findOne<User>({
+					const user = await (trxAdapter || adapter).findOne<User>({
 						model: "user",
 						where: [
 							{
@@ -635,7 +663,7 @@ export const createInternalAdapter = (
 					return null;
 				}
 			} else {
-				const user = await adapter.findOne<User>({
+				const user = await (trxAdapter || adapter).findOne<User>({
 					model: "user",
 					where: [
 						{
@@ -645,7 +673,7 @@ export const createInternalAdapter = (
 					],
 				});
 				if (user) {
-					const accounts = await adapter.findMany<Account>({
+					const accounts = await (trxAdapter || adapter).findMany<Account>({
 						model: "account",
 						where: [
 							{
@@ -666,8 +694,9 @@ export const createInternalAdapter = (
 		findUserByEmail: async (
 			email: string,
 			options?: { includeAccounts: boolean },
+			trxAdapter?: TransactionAdapter,
 		) => {
-			const user = await adapter.findOne<User>({
+			const user = await (trxAdapter || adapter).findOne<User>({
 				model: "user",
 				where: [
 					{
@@ -678,7 +707,7 @@ export const createInternalAdapter = (
 			});
 			if (!user) return null;
 			if (options?.includeAccounts) {
-				const accounts = await adapter.findMany<Account>({
+				const accounts = await (trxAdapter || adapter).findMany<Account>({
 					model: "account",
 					where: [
 						{
@@ -697,8 +726,8 @@ export const createInternalAdapter = (
 				accounts: [],
 			};
 		},
-		findUserById: async (userId: string) => {
+		findUserById: async (userId: string, trxAdapter?: TransactionAdapter) => {
-			const user = await adapter.findOne<User>({
+			const user = await (trxAdapter || adapter).findOne<User>({
 				model: "user",
 				where: [
 					{
@@ -713,6 +742,7 @@ export const createInternalAdapter = (
 			account: Omit<Account, "id" | "createdAt" | "updatedAt"> &
 				Partial<Account>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const _account = await createWithHooks(
 				{
@@ -724,6 +754,7 @@ export const createInternalAdapter = (
 				"account",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return _account;
 		},
@@ -731,6 +762,7 @@ export const createInternalAdapter = (
 			userId: string,
 			data: Partial<User> & Record<string, any>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const user = await updateWithHooks<User>(
 				data,
@@ -743,6 +775,7 @@ export const createInternalAdapter = (
 				"user",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			if (secondaryStorage && user) {
 				const listRaw = await secondaryStorage.get(`active-sessions-${userId}`);
@@ -785,6 +818,7 @@ export const createInternalAdapter = (
 			email: string,
 			data: Partial<User & Record<string, any>>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const user = await updateWithHooks<User>(
 				data,
@@ -797,6 +831,7 @@ export const createInternalAdapter = (
 				"user",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return user;
 		},
@@ -804,6 +839,7 @@ export const createInternalAdapter = (
 			userId: string,
 			password: string,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			await updateManyWithHooks(
 				{
@@ -822,10 +858,11 @@ export const createInternalAdapter = (
 				"account",
 				undefined,
 				context,
+				trxAdapter,
 			);
 		},
-		findAccounts: async (userId: string) => {
+		findAccounts: async (userId: string, trxAdapter?: TransactionAdapter) => {
-			const accounts = await adapter.findMany<Account>({
+			const accounts = await (trxAdapter || adapter).findMany<Account>({
 				model: "account",
 				where: [
 					{
@@ -836,8 +873,8 @@ export const createInternalAdapter = (
 			});
 			return accounts;
 		},
-		findAccount: async (accountId: string) => {
+		findAccount: async (accountId: string, trxAdapter?: TransactionAdapter) => {
-			const account = await adapter.findOne<Account>({
+			const account = await (trxAdapter || adapter).findOne<Account>({
 				model: "account",
 				where: [
 					{
@@ -848,8 +885,12 @@ export const createInternalAdapter = (
 			});
 			return account;
 		},
-		findAccountByProviderId: async (accountId: string, providerId: string) => {
+		findAccountByProviderId: async (
-			const account = await adapter.findOne<Account>({
+			accountId: string,
+			providerId: string,
+			trxAdapter?: TransactionAdapter,
+		) => {
+			const account = await (trxAdapter || adapter).findOne<Account>({
 				model: "account",
 				where: [
 					{
@@ -864,8 +905,11 @@ export const createInternalAdapter = (
 			});
 			return account;
 		},
-		findAccountByUserId: async (userId: string) => {
+		findAccountByUserId: async (
-			const account = await adapter.findMany<Account>({
+			userId: string,
+			trxAdapter?: TransactionAdapter,
+		) => {
+			const account = await (trxAdapter || adapter).findMany<Account>({
 				model: "account",
 				where: [
 					{
@@ -880,6 +924,7 @@ export const createInternalAdapter = (
 			id: string,
 			data: Partial<Account>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const account = await updateWithHooks<Account>(
 				data,
@@ -887,6 +932,7 @@ export const createInternalAdapter = (
 				"account",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return account;
 		},
@@ -894,6 +940,7 @@ export const createInternalAdapter = (
 			data: Omit<Verification, "createdAt" | "id" | "updatedAt"> &
 				Partial<Verification>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const verification = await createWithHooks(
 				{
@@ -905,11 +952,16 @@ export const createInternalAdapter = (
 				"verification",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return verification as Verification;
 		},
-		findVerificationValue: async (identifier: string) => {
+		findVerificationValue: async (
-			const verification = await adapter.findMany<Verification>({
+			identifier: string,
+			trxAdapter?: TransactionAdapter,
+		) => {
+			const verification = await (trxAdapter || adapter).findMany<Verification>(
+				{
 					model: "verification",
 					where: [
 						{
@@ -922,9 +974,10 @@ export const createInternalAdapter = (
 						direction: "desc",
 					},
 					limit: 1,
-			});
+				},
+			);
 			if (!options.verification?.disableCleanup) {
-				await adapter.deleteMany({
+				await (trxAdapter || adapter).deleteMany({
 					model: "verification",
 					where: [
 						{
@@ -938,8 +991,11 @@ export const createInternalAdapter = (
 			const lastVerification = verification[0];
 			return lastVerification as Verification | null;
 		},
-		deleteVerificationValue: async (id: string) => {
+		deleteVerificationValue: async (
-			await adapter.delete<Verification>({
+			id: string,
+			trxAdapter?: TransactionAdapter,
+		) => {
+			await (trxAdapter || adapter).delete<Verification>({
 				model: "verification",
 				where: [
 					{
@@ -949,8 +1005,11 @@ export const createInternalAdapter = (
 				],
 			});
 		},
-		deleteVerificationByIdentifier: async (identifier: string) => {
+		deleteVerificationByIdentifier: async (
-			await adapter.delete<Verification>({
+			identifier: string,
+			trxAdapter?: TransactionAdapter,
+		) => {
+			await (trxAdapter || adapter).delete<Verification>({
 				model: "verification",
 				where: [
 					{
@@ -964,6 +1023,7 @@ export const createInternalAdapter = (
 			id: string,
 			data: Partial<Verification>,
 			context?: GenericEndpointContext,
+			trxAdapter?: TransactionAdapter,
 		) => {
 			const verification = await updateWithHooks<Verification>(
 				data,
@@ -971,6 +1031,7 @@ export const createInternalAdapter = (
 				"verification",
 				undefined,
 				context,
+				trxAdapter,
 			);
 			return verification;
 		},

packages/better-auth/src/db/with-hooks.ts

@@ -3,6 +3,7 @@ import type {
 	BetterAuthOptions,
 	GenericEndpointContext,
 	Models,
+	TransactionAdapter,
 	Where,
 } from "../types";
 
@@ -26,6 +27,7 @@ export function getWithHooks(
 			executeMainFn?: boolean;
 		},
 		context?: GenericEndpointContext,
+		trxAdapter?: TransactionAdapter,
 	) {
 		let actualData = data;
 		for (const hook of hooks || []) {
@@ -50,7 +52,7 @@ export function getWithHooks(
 			: null;
 		const created =
 			!customCreateFn || customCreateFn.executeMainFn
-				? await adapter.create<T>({
+				? await (trxAdapter || adapter).create<T>({
 						model,
 						data: actualData as any,
 						forceAllowId: true,
@@ -76,6 +78,7 @@ export function getWithHooks(
 			executeMainFn?: boolean;
 		},
 		context?: GenericEndpointContext,
+		trxAdapter?: TransactionAdapter,
 	) {
 		let actualData = data;
 
@@ -97,7 +100,7 @@ export function getWithHooks(
 
 		const updated =
 			!customUpdateFn || customUpdateFn.executeMainFn
-				? await adapter.update<T>({
+				? await (trxAdapter || adapter).update<T>({
 						model,
 						update: actualData,
 						where,
@@ -122,6 +125,7 @@ export function getWithHooks(
 			executeMainFn?: boolean;
 		},
 		context?: GenericEndpointContext,
+		trxAdapter?: TransactionAdapter,
 	) {
 		let actualData = data;
 
@@ -143,7 +147,7 @@ export function getWithHooks(
 
 		const updated =
 			!customUpdateFn || customUpdateFn.executeMainFn
-				? await adapter.updateMany({
+				? await (trxAdapter || adapter).updateMany({
 						model,
 						update: actualData,
 						where,

packages/better-auth/src/types/adapter.ts

@@ -70,6 +70,13 @@ export type Adapter = {
 	}) => Promise<number>;
 	delete: <T>(data: { model: string; where: Where[] }) => Promise<void>;
 	deleteMany: (data: { model: string; where: Where[] }) => Promise<number>;
+	/**
+	 * Execute multiple operations in a transaction.
+	 * If the adapter doesn't support transactions, operations will be executed sequentially.
+	 */
+	transaction: <R>(
+		callback: (tx: Omit<Adapter, "transaction">) => Promise<R>,
+	) => Promise<R>;
 	/**
 	 *
 	 * @param options
@@ -84,6 +91,8 @@ export type Adapter = {
 	} & CustomAdapter["options"];
 };
 
+export type TransactionAdapter = Omit<Adapter, "transaction">;
+
 export type AdapterSchemaCreation = {
 	/**
 	 * Code to be inserted into the file