diff --git a/barrelsby.json b/barrelsby.json
index 3a93788f..24e4334a 100644
--- a/barrelsby.json
+++ b/barrelsby.json
@@ -1,6 +1,7 @@
 {
   "directory": [
     "./src/data/repositories",
+    "./src/data/repositories/interfaces",
     "./src/data/services/api",
     "./src/data/dto/auth",
     "./src/data/dto/chat",
diff --git a/src/data/repositories/auth_repository.ts b/src/data/repositories/auth_repository.ts
index 4e47847a..d63c0c76 100644
--- a/src/data/repositories/auth_repository.ts
+++ b/src/data/repositories/auth_repository.ts
@@ -27,6 +27,7 @@ import { RegisterRequest } from "@/data/dto/auth/register_request";
 import { SendCodeRequest } from "@/data/dto/auth/send_code_request";
 import { User } from "@/data/dto/user/user";
 import { Result } from "@/utils/result";
+import type { IAuthRepository } from "@/data/repositories/interfaces/iauth_repository";
 import { AuthStorage } from "@/data/storage/auth/auth_storage";
 import type { IAuthStorage } from "@/data/storage/auth/iauth_storage";
 import { UserStorage } from "@/data/storage/user/user_storage";
@@ -35,7 +36,7 @@ import type { IUserStorage } from "@/data/storage/user/iuser_storage";
 /** 硬编码平台名，对齐 Dart `PlatformUtil.platformName.toLowerCase()`（Web 平台）。 */
 const WEB_PLATFORM = "web";
 
-export class AuthRepository {
+export class AuthRepository implements IAuthRepository {
   constructor(
     private readonly api: AuthApi,
     private readonly storage: IAuthStorage,
diff --git a/src/data/repositories/chat_repository.ts b/src/data/repositories/chat_repository.ts
index 64ee94c4..1c2fb6e7 100644
--- a/src/data/repositories/chat_repository.ts
+++ b/src/data/repositories/chat_repository.ts
@@ -21,10 +21,11 @@ import { ChatMessage } from "@/data/dto/chat/chat_message";
 import { ChatSendResponse } from "@/data/dto/chat/chat_send_response";
 import { SendMessageRequest } from "@/data/dto/chat/send_message_request";
 import { Result } from "@/utils/result";
+import type { IChatRepository } from "@/data/repositories/interfaces/ichat_repository";
 import { LocalChatStorage } from "@/data/storage/chat/local_chat_storage";
 import { LocalMessage } from "@/data/storage/chat/local_message";
 
-export class ChatRepository {
+export class ChatRepository implements IChatRepository {
   constructor(
     private readonly api: ChatApi,
     private readonly localStorage: LocalChatStorage,
diff --git a/src/data/repositories/index.ts b/src/data/repositories/index.ts
index 6922ab27..a45833f1 100644
--- a/src/data/repositories/index.ts
+++ b/src/data/repositories/index.ts
@@ -6,3 +6,7 @@ export * from "./auth_repository";
 export * from "./chat_repository";
 export * from "./metrics_repository";
 export * from "./user_repository";
+export * from "./interfaces/iauth_repository";
+export * from "./interfaces/ichat_repository";
+export * from "./interfaces/imetrics_repository";
+export * from "./interfaces/iuser_repository";
diff --git a/src/data/repositories/interfaces/iauth_repository.ts b/src/data/repositories/interfaces/iauth_repository.ts
new file mode 100644
index 00000000..ecf2cf9a
--- /dev/null
+++ b/src/data/repositories/interfaces/iauth_repository.ts
@@ -0,0 +1,76 @@
+"use client";
+
+/**
+ * IAuthRepository 接口
+ *
+ * 对齐 Dart 端 `AuthRepository` 抽象（lib/data/repositories/auth_repository.dart）：
+ *   - 登录 / 登出 / 刷新 token / 第三方 OAuth 登录的公共契约
+ *   - 登出强制清本地态（无论 API 成败）
+ *   - `getCurrentUser` 成功后尽力写本地 User 缓存（best-effort）
+ *   - 所有方法返回 `Promise<Result<T>>`，与 Dart `Future<Result<T>>` 对齐
+ *
+ * 注：仓库内私有方法（`_socialLogin` / `_saveLoginData`）不暴露在接口上。
+ * 原始 Dart: lib/data/repositories/auth_repository_impl.dart
+ */
+
+import type { Result } from "@/utils/result";
+import type { GuestLoginResponse } from "@/data/dto/auth/guest_login_response";
+import type { LoginResponse } from "@/data/dto/auth/login_response";
+import type { RefreshTokenResponse } from "@/data/dto/auth/refresh_token_response";
+import type { User } from "@/data/dto/user/user";
+
+export interface IAuthRepository {
+  /** 用户注册。注册成功不会自动登录（与 Dart 行为一致）。 */
+  register(input: {
+    username: string;
+    email: string;
+    password: string;
+    guestId?: string;
+  }): Promise<Result<void>>;
+
+  /** 邮箱/用户名 + 密码登录。 */
+  emailLogin(input: {
+    email?: string;
+    username?: string;
+    password: string;
+    guestId?: string;
+  }): Promise<Result<LoginResponse>>;
+
+  /** 发送邮箱验证码。 */
+  sendCode(email: string): Promise<Result<void>>;
+
+  /**
+   * 退出登录：先调 API 注销服务端会话，**无论成败**都清本地登录态。
+   */
+  logout(): Promise<Result<void>>;
+
+  /** 游客登录：使用 deviceId 换取 guest token。 */
+  guestLogin(deviceId: string): Promise<Result<GuestLoginResponse>>;
+
+  /** Google 登录。 */
+  googleLogin(input: {
+    idToken: string;
+    guestId?: string;
+  }): Promise<Result<LoginResponse>>;
+
+  /** Facebook 登录（accessToken 流程）。 */
+  facebookLogin(input: {
+    accessToken: string;
+    guestId?: string;
+  }): Promise<Result<LoginResponse>>;
+
+  /** Facebook ID 登录（v7.0 新增，fbId 流程）。 */
+  facebookIdLogin(input: {
+    fbId: string;
+    avatarUrl?: string;
+  }): Promise<Result<LoginResponse>>;
+
+  /** Apple 登录。 */
+  appleLogin(identityToken: string): Promise<Result<LoginResponse>>;
+
+  /** 刷新 token：先读本地的 refresh token，空则返回错误。 */
+  refreshToken(): Promise<Result<RefreshTokenResponse>>;
+
+  /** 获取当前登录用户。成功后尽力写本地 User 缓存。 */
+  getCurrentUser(): Promise<Result<User>>;
+}
diff --git a/src/data/repositories/interfaces/ichat_repository.ts b/src/data/repositories/interfaces/ichat_repository.ts
new file mode 100644
index 00000000..a0f52360
--- /dev/null
+++ b/src/data/repositories/interfaces/ichat_repository.ts
@@ -0,0 +1,43 @@
+"use client";
+
+/**
+ * IChatRepository 接口
+ *
+ * 对齐 Dart 端 `ChatRepository` 抽象（lib/data/repositories/chat_repository.dart）：
+ *   - 远程：发送消息、获取历史
+ *   - 本地：写入 / 批量覆盖 / 读取 / 清空 / 计数
+ *
+ * 私有助手（`_chatToLocal` / `_localToChat` / `_mapLocalStorageResult`）不暴露。
+ * 原始 Dart: lib/data/repositories/chat_repository_impl.dart
+ */
+
+import type { Result } from "@/utils/result";
+import type { ChatHistoryResponse } from "@/data/dto/chat/chat_history_response";
+import type { ChatMessage } from "@/data/dto/chat/chat_message";
+import type { ChatSendResponse } from "@/data/dto/chat/chat_send_response";
+
+export interface IChatRepository {
+  /** 发送一条消息。 */
+  sendMessage(
+    message: string,
+    options?: { image?: string; useWebSocket?: boolean },
+  ): Promise<Result<ChatSendResponse>>;
+
+  /** 获取聊天历史，分页参数默认 limit=50, offset=0。 */
+  getHistory(limit?: number, offset?: number): Promise<Result<ChatHistoryResponse>>;
+
+  /** 把一条消息写入本地存储。 */
+  saveMessageToLocal(message: ChatMessage): Promise<Result<void>>;
+
+  /** 批量覆盖写入：先清空本地存储，再写入新列表。 */
+  saveMessagesToLocal(messages: readonly ChatMessage[]): Promise<Result<void>>;
+
+  /** 读取所有本地消息，按 dbId 升序。 */
+  getLocalMessages(): Promise<Result<ChatMessage[]>>;
+
+  /** 清空本地消息。 */
+  clearLocalMessages(): Promise<Result<void>>;
+
+  /** 获取本地消息数量。 */
+  getLocalMessageCount(): Promise<Result<number>>;
+}
diff --git a/src/data/repositories/interfaces/imetrics_repository.ts b/src/data/repositories/interfaces/imetrics_repository.ts
new file mode 100644
index 00000000..070289c8
--- /dev/null
+++ b/src/data/repositories/interfaces/imetrics_repository.ts
@@ -0,0 +1,29 @@
+"use client";
+
+/**
+ * IMetricsRepository 接口
+ *
+ * 对齐 Dart 端 `MetricsRepository` 抽象（lib/data/repositories/metrics_repository.dart）：
+ *   - 纯远程 fire-and-forget 上报，无本地状态
+ *
+ * 原始 Dart: lib/data/repositories/metrics_repository_impl.dart
+ */
+
+import type { Result } from "@/utils/result";
+
+export interface IMetricsRepository {
+  /** 上报 PWA 事件。自动注入当前秒级时间戳。 */
+  reportPwaEvent(input: {
+    deviceId: string;
+    deviceType: string;
+    pwaInstalled: boolean;
+    pwaSupported: boolean;
+  }): Promise<Result<void>>;
+
+  /** 上报用户环境信息（浏览器、UA 等）。 */
+  reportUserInfo(input: {
+    userId: string;
+    browser: string;
+    userAgent: string;
+  }): Promise<Result<void>>;
+}
diff --git a/src/data/repositories/interfaces/index.ts b/src/data/repositories/interfaces/index.ts
new file mode 100644
index 00000000..3d0eb5b3
--- /dev/null
+++ b/src/data/repositories/interfaces/index.ts
@@ -0,0 +1,8 @@
+/**
+ * @file Automatically generated by barrelsby.
+ */
+
+export * from "./iauth_repository";
+export * from "./ichat_repository";
+export * from "./imetrics_repository";
+export * from "./iuser_repository";
diff --git a/src/data/repositories/interfaces/iuser_repository.ts b/src/data/repositories/interfaces/iuser_repository.ts
new file mode 100644
index 00000000..ce1aefe7
--- /dev/null
+++ b/src/data/repositories/interfaces/iuser_repository.ts
@@ -0,0 +1,37 @@
+"use client";
+
+/**
+ * IUserRepository 接口
+ *
+ * 对齐 Dart 端 `UserRepository` 抽象（lib/data/repositories/user_repository.dart）：
+ *   - 纯远程调用，不直接写本地 storage（持久化由 AuthRepository 在登录流程中处理）
+ *
+ * 原始 Dart: lib/data/repositories/user_repository_impl.dart
+ */
+
+import type { Result } from "@/utils/result";
+import type { CreditsData } from "@/data/dto/user/credits_data";
+import type { CreditsHistoryData } from "@/data/dto/user/credits_history_data";
+import type { UpdateProfileRequest } from "@/data/dto/user/update_profile_request";
+import type { User } from "@/data/dto/user/user";
+import type { UserStatsResponse } from "@/data/dto/user/user_stats_response";
+
+export interface IUserRepository {
+  /** 获取用户统计信息。 */
+  getUserStats(): Promise<Result<UserStatsResponse>>;
+
+  /** 获取当前登录用户信息。 */
+  getCurrentUser(): Promise<Result<User>>;
+
+  /** 更新个人资料。 */
+  updateProfile(request: UpdateProfileRequest): Promise<Result<User>>;
+
+  /** 查询积分余额。 */
+  getCredits(): Promise<Result<CreditsData>>;
+
+  /** 查询积分操作历史，分页参数默认 limit=50, offset=0。 */
+  getCreditsHistory(
+    limit?: number,
+    offset?: number,
+  ): Promise<Result<CreditsHistoryData>>;
+}
diff --git a/src/data/repositories/metrics_repository.ts b/src/data/repositories/metrics_repository.ts
index 42e96848..508a4c34 100644
--- a/src/data/repositories/metrics_repository.ts
+++ b/src/data/repositories/metrics_repository.ts
@@ -11,8 +11,9 @@ import { MetricsApi, metricsApi } from "@/data/services/api";
 import { AppEvent } from "@/data/dto/metrics/app_event";
 import { PwaEvent } from "@/data/dto/metrics/pwa_event";
 import { Result } from "@/utils/result";
+import type { IMetricsRepository } from "@/data/repositories/interfaces/imetrics_repository";
 
-export class MetricsRepository {
+export class MetricsRepository implements IMetricsRepository {
   constructor(private readonly api: MetricsApi) {}
 
   /**
diff --git a/src/data/repositories/user_repository.ts b/src/data/repositories/user_repository.ts
index c68d5e98..b0bab76c 100644
--- a/src/data/repositories/user_repository.ts
+++ b/src/data/repositories/user_repository.ts
@@ -15,8 +15,9 @@ import { UpdateProfileRequest } from "@/data/dto/user/update_profile_request";
 import { User } from "@/data/dto/user/user";
 import { UserStatsResponse } from "@/data/dto/user/user_stats_response";
 import { Result } from "@/utils/result";
+import type { IUserRepository } from "@/data/repositories/interfaces/iuser_repository";
 
-export class UserRepository {
+export class UserRepository implements IUserRepository {
   constructor(private readonly api: UserApi) {}
 
   /** 获取用户统计信息。 */
diff --git a/src/stores/auth/auth-machine.ts b/src/stores/auth/auth-machine.ts
index 16ed3c65..1656e364 100644
--- a/src/stores/auth/auth-machine.ts
+++ b/src/stores/auth/auth-machine.ts
@@ -14,6 +14,7 @@ import { signIn } from "next-auth/react";
 import type { AuthProvider } from "@/lib/auth/auth_platform";
 import type { LoginStatus } from "@/models/auth/login-status";
 import { authRepository } from "@/data/repositories/auth_repository";
+import type { IAuthRepository } from "@/data/repositories/interfaces";
 import { AuthStorage } from "@/data/storage/auth/auth_storage";
 import { deviceIdentifier } from "@/utils/device_identifier";
 import { Result } from "@/utils/result";
@@ -40,11 +41,13 @@ async function readGuestId(): Promise<string | undefined> {
 // ============================================================
 // Actors（异步服务）
 // ============================================================
+// 仓库以接口类型注入：调用面只看接口，运行时仍是同一单例
+const authRepo: IAuthRepository = authRepository;
 
 const emailLoginActor = fromPromise<LoginStatus, { email: string; password: string }>(
   async ({ input }) => {
     const guestId = await readGuestId();
-    const result = await authRepository.emailLogin({ ...input, guestId });
+    const result = await authRepo.emailLogin({ ...input, guestId });
     if (Result.isErr(result)) throw result.error;
     return "email" as LoginStatus;
   },
@@ -56,11 +59,11 @@ const emailRegisterThenLoginActor = fromPromise<
 >(async ({ input }) => {
   const guestId = await readGuestId();
 
-  const registerResult = await authRepository.register({ ...input, guestId });
+  const registerResult = await authRepo.register({ ...input, guestId });
   if (Result.isErr(registerResult)) throw registerResult.error;
 
   // 注册后自动登录（对齐 Dart 行为）
-  const loginResult = await authRepository.emailLogin({
+  const loginResult = await authRepo.emailLogin({
     email: input.email,
     password: input.password,
     guestId,
@@ -84,7 +87,7 @@ const oauthSignInActor = fromPromise<void, AuthProvider>(async ({ input }) => {
 const syncGoogleBackendActor = fromPromise<LoginStatus, { idToken: string }>(
   async ({ input }) => {
     const guestId = await readGuestId();
-    const result = await authRepository.googleLogin({
+    const result = await authRepo.googleLogin({
       idToken: input.idToken,
       guestId,
     });
@@ -98,7 +101,7 @@ const syncFacebookBackendActor = fromPromise<
   { accessToken: string }
 >(async ({ input }) => {
   const guestId = await readGuestId();
-  const result = await authRepository.facebookLogin({
+  const result = await authRepo.facebookLogin({
     accessToken: input.accessToken,
     guestId,
   });
diff --git a/src/stores/chat/chat-machine.ts b/src/stores/chat/chat-machine.ts
index 6ed38a8a..20940fa0 100644
--- a/src/stores/chat/chat-machine.ts
+++ b/src/stores/chat/chat-machine.ts
@@ -18,6 +18,7 @@ import { setup, fromPromise, assign } from "xstate";
 
 import type { UiMessage } from "@/models/chat/ui-message";
 import { chatRepository } from "@/data/repositories/chat_repository";
+import type { IChatRepository } from "@/data/repositories/interfaces";
 import { ChatStorage } from "@/data/storage/chat/chat_storage";
 import { AuthStorage } from "@/data/storage/auth/auth_storage";
 import { formatDate } from "@/utils/date";
@@ -72,6 +73,9 @@ function mapTotalQuotaResult(
   return fallback;
 }
 
+// 仓库以接口类型注入：调用面只看接口，运行时仍是同一单例
+const chatRepo: IChatRepository = chatRepository;
+
 interface InitResult {
   localMessages: UiMessage[];
   isGuest: boolean;
@@ -86,7 +90,7 @@ async function readInitData(): Promise<InitResult> {
   const [dailyResult, totalResult, localResult] = await Promise.all([
     chatStorage.getGuestDailyChatQuota(),
     chatStorage.getGuestTotalQuota(),
-    isGuest ? chatRepository.getLocalMessages() : Promise.resolve(null),
+    isGuest ? chatRepo.getLocalMessages() : Promise.resolve(null),
   ]);
 
   return {
@@ -115,11 +119,11 @@ const sendMessageHttpActor = fromPromise<
   { messages: UiMessage[] },
   { content: string }
 >(async ({ input }) => {
-  const result = await chatRepository.sendMessage(input.content);
+  const result = await chatRepo.sendMessage(input.content);
   if (Result.isErr(result)) throw result.error;
 
   // 拉取最新本地历史
-  const local = await chatRepository.getLocalMessages();
+  const local = await chatRepo.getLocalMessages();
   if (Result.isOk(local) && local.data) {
     return { messages: localMessagesToUi(local.data) };
   }
@@ -130,7 +134,7 @@ const loadMoreHistoryActor = fromPromise<
   { messages: UiMessage[]; hasMore: boolean; newOffset: number },
   { offset: number }
 >(async ({ input }) => {
-  const result = await chatRepository.getHistory(PAGE_SIZE, input.offset);
+  const result = await chatRepo.getHistory(PAGE_SIZE, input.offset);
   if (Result.isErr(result)) throw result.error;
 
   const page = localMessagesToUi(result.data.messages);
diff --git a/src/stores/user/user-machine.ts b/src/stores/user/user-machine.ts
index b410da47..e403eb78 100644
--- a/src/stores/user/user-machine.ts
+++ b/src/stores/user/user-machine.ts
@@ -14,6 +14,10 @@ import { setup, fromPromise, assign } from "xstate";
 import type { UserView } from "@/models/user/user";
 import { userRepository } from "@/data/repositories/user_repository";
 import { authRepository } from "@/data/repositories/auth_repository";
+import type {
+  IAuthRepository,
+  IUserRepository,
+} from "@/data/repositories/interfaces";
 import { UserStorage } from "@/data/storage/user/user_storage";
 import { Result } from "@/utils/result";
 
@@ -81,10 +85,14 @@ async function readInitData(): Promise<InitData> {
 // ============================================================
 // Actors
 // ============================================================
+// 仓库以接口类型注入：调用面只看接口，运行时仍是同一单例
+const userRepo: IUserRepository = userRepository;
+const authRepo: IAuthRepository = authRepository;
+
 const userInitActor = fromPromise<InitData>(async () => readInitData());
 
 const userFetchActor = fromPromise<UserView | null>(async () => {
-  const result = await userRepository.getCurrentUser();
+  const result = await userRepo.getCurrentUser();
   if (Result.isErr(result)) return null;
   const view = toView(result.data.toJson());
   // 持久化到本地
@@ -93,7 +101,7 @@ const userFetchActor = fromPromise<UserView | null>(async () => {
 });
 
 const userLogoutActor = fromPromise<void>(async () => {
-  await authRepository.logout();
+  await authRepo.logout();
   await userStorage.clearUserData();
 });