diff --git a/packages/server/src/app.module.ts b/packages/server/src/app.module.ts
index 42ce717..119cbd5 100644
--- a/packages/server/src/app.module.ts
+++ b/packages/server/src/app.module.ts
@@ -2,6 +2,9 @@ import { Module } from '@nestjs/common'
 import { ConfigModule } from '@nestjs/config'
 import { AppController } from './app.controller'
 import { PrismaModule } from './prisma/prisma.module'
+import { UserModule } from './user/user.module'
+import { AuthModule } from './auth/auth.module'
+import { StudioModule } from './studio/studio.module'
 
 @Module({
   imports: [
@@ -10,6 +13,9 @@ import { PrismaModule } from './prisma/prisma.module'
       envFilePath: ['.env.local', '.env'],
     }),
     PrismaModule,
+    AuthModule,
+    UserModule,
+    StudioModule,
   ],
   controllers: [AppController],
 })
diff --git a/packages/server/src/auth/__tests__/auth.service.spec.ts b/packages/server/src/auth/__tests__/auth.service.spec.ts
new file mode 100644
index 0000000..1e7f06c
--- /dev/null
+++ b/packages/server/src/auth/__tests__/auth.service.spec.ts
@@ -0,0 +1,220 @@
+import { Test, TestingModule } from '@nestjs/testing'
+import { JwtService } from '@nestjs/jwt'
+import { UnauthorizedException } from '@nestjs/common'
+import { UserRole } from '@mp-pilates/shared'
+import { AuthService } from '../auth.service'
+import { WechatService } from '../wechat.service'
+import { PrismaService } from '../../prisma/prisma.service'
+
+// ─── Fixtures ────────────────────────────────────────────────────────────────
+
+const OPENID = 'test_openid_123'
+const SESSION_KEY = 'test_session_key'
+const USER_ID = 'user-uuid-001'
+const JWT_TOKEN = 'signed.jwt.token'
+
+const mockUser = {
+  id: USER_ID,
+  openid: OPENID,
+  unionid: null,
+  phone: null,
+  nickname: '',
+  avatarUrl: null,
+  role: UserRole.MEMBER,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+}
+
+// ─── Mocks ───────────────────────────────────────────────────────────────────
+
+const mockPrismaService = {
+  user: {
+    findUnique: jest.fn(),
+    findUniqueOrThrow: jest.fn(),
+    create: jest.fn(),
+    update: jest.fn(),
+  },
+}
+
+const mockWechatService = {
+  code2Session: jest.fn(),
+  decryptData: jest.fn(),
+}
+
+const mockJwtService = {
+  sign: jest.fn(),
+}
+
+// ─── Tests ───────────────────────────────────────────────────────────────────
+
+describe('AuthService', () => {
+  let authService: AuthService
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        AuthService,
+        { provide: PrismaService, useValue: mockPrismaService },
+        { provide: WechatService, useValue: mockWechatService },
+        { provide: JwtService, useValue: mockJwtService },
+      ],
+    }).compile()
+
+    authService = module.get<AuthService>(AuthService)
+
+    jest.clearAllMocks()
+    mockJwtService.sign.mockReturnValue(JWT_TOKEN)
+  })
+
+  // ── login ──────────────────────────────────────────────────────────────────
+
+  describe('login', () => {
+    const loginCode = 'wx_login_code_abc'
+
+    beforeEach(() => {
+      mockWechatService.code2Session.mockResolvedValue({
+        openid: OPENID,
+        sessionKey: SESSION_KEY,
+      })
+    })
+
+    it('creates a new user when openid is not found', async () => {
+      mockPrismaService.user.findUnique.mockResolvedValue(null)
+      mockPrismaService.user.create.mockResolvedValue(mockUser)
+
+      const result = await authService.login(loginCode)
+
+      expect(mockWechatService.code2Session).toHaveBeenCalledWith(loginCode)
+      expect(mockPrismaService.user.findUnique).toHaveBeenCalledWith({
+        where: { openid: OPENID },
+      })
+      expect(mockPrismaService.user.create).toHaveBeenCalledWith({
+        data: { openid: OPENID },
+      })
+      expect(result.user).toEqual(mockUser)
+    })
+
+    it('creates user with unionid when present', async () => {
+      const unionid = 'wx_union_id_xyz'
+      mockWechatService.code2Session.mockResolvedValue({
+        openid: OPENID,
+        sessionKey: SESSION_KEY,
+        unionid,
+      })
+      mockPrismaService.user.findUnique.mockResolvedValue(null)
+      mockPrismaService.user.create.mockResolvedValue({ ...mockUser, unionid })
+
+      await authService.login(loginCode)
+
+      expect(mockPrismaService.user.create).toHaveBeenCalledWith({
+        data: { openid: OPENID, unionid },
+      })
+    })
+
+    it('returns existing user when openid already exists', async () => {
+      mockPrismaService.user.findUnique.mockResolvedValue(mockUser)
+
+      const result = await authService.login(loginCode)
+
+      expect(mockPrismaService.user.findUnique).toHaveBeenCalledWith({
+        where: { openid: OPENID },
+      })
+      expect(mockPrismaService.user.create).not.toHaveBeenCalled()
+      expect(result.user).toEqual(mockUser)
+    })
+
+    it('returns a valid JWT token', async () => {
+      mockPrismaService.user.findUnique.mockResolvedValue(mockUser)
+
+      const result = await authService.login(loginCode)
+
+      expect(mockJwtService.sign).toHaveBeenCalledWith({
+        sub: USER_ID,
+        role: UserRole.MEMBER,
+      })
+      expect(result.token).toBe(JWT_TOKEN)
+    })
+
+    it('returns both token and user in result', async () => {
+      mockPrismaService.user.findUnique.mockResolvedValue(mockUser)
+
+      const result = await authService.login(loginCode)
+
+      expect(result).toEqual({
+        token: JWT_TOKEN,
+        user: mockUser,
+      })
+    })
+  })
+
+  // ── bindPhone ──────────────────────────────────────────────────────────────
+
+  describe('bindPhone', () => {
+    const encryptedData = 'encrypted_phone_data'
+    const iv = 'init_vector'
+    const phoneNumber = '+8613800138000'
+
+    beforeEach(async () => {
+      // Seed the in-memory session key store by running login first
+      mockWechatService.code2Session.mockResolvedValue({
+        openid: OPENID,
+        sessionKey: SESSION_KEY,
+      })
+      mockPrismaService.user.findUnique.mockResolvedValue(mockUser)
+      mockJwtService.sign.mockReturnValue(JWT_TOKEN)
+      await authService.login('login_code')
+    })
+
+    it('updates phone number and returns the updated user', async () => {
+      const updatedUser = { ...mockUser, phone: phoneNumber }
+
+      mockWechatService.decryptData.mockReturnValue({
+        phoneNumber,
+        purePhoneNumber: '13800138000',
+        countryCode: '86',
+      })
+      mockPrismaService.user.update.mockResolvedValue(updatedUser)
+
+      const result = await authService.bindPhone(USER_ID, encryptedData, iv)
+
+      expect(mockWechatService.decryptData).toHaveBeenCalledWith(
+        SESSION_KEY,
+        encryptedData,
+        iv,
+      )
+      expect(mockPrismaService.user.update).toHaveBeenCalledWith({
+        where: { id: USER_ID },
+        data: { phone: phoneNumber },
+      })
+      expect(result).toEqual(updatedUser)
+    })
+
+    it('throws UnauthorizedException when session key is not found', async () => {
+      const unknownUserId = 'unknown-user-id'
+
+      await expect(
+        authService.bindPhone(unknownUserId, encryptedData, iv),
+      ).rejects.toThrow(UnauthorizedException)
+    })
+
+    it('does not mutate the original user object', async () => {
+      const originalUser = { ...mockUser }
+      const updatedUser = { ...mockUser, phone: phoneNumber }
+
+      mockWechatService.decryptData.mockReturnValue({
+        phoneNumber,
+        purePhoneNumber: '13800138000',
+        countryCode: '86',
+      })
+      mockPrismaService.user.update.mockResolvedValue(updatedUser)
+
+      const result = await authService.bindPhone(USER_ID, encryptedData, iv)
+
+      // Original mock user should be unchanged
+      expect(mockUser.phone).toBeNull()
+      // Result is a new object with the updated phone
+      expect(result.phone).toBe(phoneNumber)
+      expect(result).not.toBe(originalUser)
+    })
+  })
+})
diff --git a/packages/server/src/auth/auth.controller.ts b/packages/server/src/auth/auth.controller.ts
new file mode 100644
index 0000000..b34f90a
--- /dev/null
+++ b/packages/server/src/auth/auth.controller.ts
@@ -0,0 +1,44 @@
+import {
+  Controller,
+  Post,
+  Body,
+  UseGuards,
+  Request,
+  HttpCode,
+  HttpStatus,
+} from '@nestjs/common'
+import { AuthService } from './auth.service'
+import { LoginDto } from './dto/login.dto'
+import { BindPhoneDto } from './dto/bind-phone.dto'
+import { JwtAuthGuard } from './jwt-auth.guard'
+import { AuthenticatedUser } from './jwt.strategy'
+import { User } from '@prisma/client'
+
+interface AuthenticatedRequest {
+  user: AuthenticatedUser
+}
+
+@Controller('auth')
+export class AuthController {
+  constructor(private readonly authService: AuthService) {}
+
+  @Post('login')
+  @HttpCode(HttpStatus.OK)
+  async login(@Body() loginDto: LoginDto): Promise<{ token: string; user: User }> {
+    return this.authService.login(loginDto.code)
+  }
+
+  @Post('phone')
+  @UseGuards(JwtAuthGuard)
+  @HttpCode(HttpStatus.OK)
+  async bindPhone(
+    @Request() req: AuthenticatedRequest,
+    @Body() bindPhoneDto: BindPhoneDto,
+  ): Promise<User> {
+    return this.authService.bindPhone(
+      req.user.userId,
+      bindPhoneDto.encryptedData,
+      bindPhoneDto.iv,
+    )
+  }
+}
diff --git a/packages/server/src/auth/auth.module.ts b/packages/server/src/auth/auth.module.ts
new file mode 100644
index 0000000..a27a374
--- /dev/null
+++ b/packages/server/src/auth/auth.module.ts
@@ -0,0 +1,28 @@
+import { Module } from '@nestjs/common'
+import { PassportModule } from '@nestjs/passport'
+import { JwtModule } from '@nestjs/jwt'
+import { ConfigModule, ConfigService } from '@nestjs/config'
+import { AuthService } from './auth.service'
+import { AuthController } from './auth.controller'
+import { WechatService } from './wechat.service'
+import { JwtStrategy } from './jwt.strategy'
+import { JwtAuthGuard } from './jwt-auth.guard'
+import { RolesGuard } from './roles.guard'
+
+@Module({
+  imports: [
+    PassportModule,
+    JwtModule.registerAsync({
+      imports: [ConfigModule],
+      inject: [ConfigService],
+      useFactory: (configService: ConfigService) => ({
+        secret: configService.getOrThrow<string>('JWT_SECRET'),
+        signOptions: { expiresIn: '7d' },
+      }),
+    }),
+  ],
+  controllers: [AuthController],
+  providers: [AuthService, WechatService, JwtStrategy, JwtAuthGuard, RolesGuard],
+  exports: [JwtStrategy, JwtAuthGuard, RolesGuard, AuthService],
+})
+export class AuthModule {}
diff --git a/packages/server/src/auth/auth.service.ts b/packages/server/src/auth/auth.service.ts
new file mode 100644
index 0000000..a04463b
--- /dev/null
+++ b/packages/server/src/auth/auth.service.ts
@@ -0,0 +1,82 @@
+import { Injectable, UnauthorizedException } from '@nestjs/common'
+import { JwtService } from '@nestjs/jwt'
+import { User } from '@prisma/client'
+import { UserRole } from '@mp-pilates/shared'
+import { PrismaService } from '../prisma/prisma.service'
+import { WechatService } from './wechat.service'
+
+export interface LoginResult {
+  token: string
+  user: User
+}
+
+export interface JwtPayload {
+  sub: string
+  role: UserRole
+}
+
+/**
+ * In-memory session key store.
+ * TODO: Replace with Redis for production multi-instance deployments.
+ *       Key: userId, Value: WeChat sessionKey
+ */
+const sessionKeyStore = new Map<string, string>()
+
+@Injectable()
+export class AuthService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly jwtService: JwtService,
+    private readonly wechatService: WechatService,
+  ) {}
+
+  async login(code: string): Promise<LoginResult> {
+    const { openid, unionid, sessionKey } =
+      await this.wechatService.code2Session(code)
+
+    const existingUser = await this.prisma.user.findUnique({
+      where: { openid },
+    })
+
+    const user =
+      existingUser ??
+      (await this.prisma.user.create({
+        data: {
+          openid,
+          ...(unionid !== undefined && { unionid }),
+        },
+      }))
+
+    sessionKeyStore.set(user.id, sessionKey)
+
+    const payload: JwtPayload = { sub: user.id, role: user.role as UserRole }
+    const token = this.jwtService.sign(payload)
+
+    return { token, user }
+  }
+
+  async bindPhone(
+    userId: string,
+    encryptedData: string,
+    iv: string,
+  ): Promise<User> {
+    const sessionKey = sessionKeyStore.get(userId)
+
+    if (!sessionKey) {
+      throw new UnauthorizedException(
+        'Session expired. Please log in again to bind your phone number.',
+      )
+    }
+
+    const phoneInfo = this.wechatService.decryptData(
+      sessionKey,
+      encryptedData,
+      iv,
+    )
+
+    return this.prisma.user.update({
+      where: { id: userId },
+      data: { phone: phoneInfo.phoneNumber },
+    })
+  }
+}
diff --git a/packages/server/src/auth/dto/bind-phone.dto.ts b/packages/server/src/auth/dto/bind-phone.dto.ts
new file mode 100644
index 0000000..a57772e
--- /dev/null
+++ b/packages/server/src/auth/dto/bind-phone.dto.ts
@@ -0,0 +1,11 @@
+import { IsString, IsNotEmpty } from 'class-validator'
+
+export class BindPhoneDto {
+  @IsString()
+  @IsNotEmpty()
+  encryptedData!: string
+
+  @IsString()
+  @IsNotEmpty()
+  iv!: string
+}
diff --git a/packages/server/src/auth/dto/login.dto.ts b/packages/server/src/auth/dto/login.dto.ts
new file mode 100644
index 0000000..78f83b9
--- /dev/null
+++ b/packages/server/src/auth/dto/login.dto.ts
@@ -0,0 +1,7 @@
+import { IsString, IsNotEmpty } from 'class-validator'
+
+export class LoginDto {
+  @IsString()
+  @IsNotEmpty()
+  code!: string
+}
diff --git a/packages/server/src/auth/jwt-auth.guard.ts b/packages/server/src/auth/jwt-auth.guard.ts
new file mode 100644
index 0000000..aa859f7
--- /dev/null
+++ b/packages/server/src/auth/jwt-auth.guard.ts
@@ -0,0 +1,5 @@
+import { Injectable } from '@nestjs/common'
+import { AuthGuard } from '@nestjs/passport'
+
+@Injectable()
+export class JwtAuthGuard extends AuthGuard('jwt') {}
diff --git a/packages/server/src/auth/jwt.strategy.ts b/packages/server/src/auth/jwt.strategy.ts
new file mode 100644
index 0000000..5cdbaba
--- /dev/null
+++ b/packages/server/src/auth/jwt.strategy.ts
@@ -0,0 +1,29 @@
+import { Injectable } from '@nestjs/common'
+import { PassportStrategy } from '@nestjs/passport'
+import { ExtractJwt, Strategy } from 'passport-jwt'
+import { ConfigService } from '@nestjs/config'
+import { UserRole } from '@mp-pilates/shared'
+import { JwtPayload } from './auth.service'
+
+export interface AuthenticatedUser {
+  userId: string
+  role: UserRole
+}
+
+@Injectable()
+export class JwtStrategy extends PassportStrategy(Strategy) {
+  constructor(configService: ConfigService) {
+    super({
+      jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken(),
+      ignoreExpiration: false,
+      secretOrKey: configService.getOrThrow<string>('JWT_SECRET'),
+    })
+  }
+
+  validate(payload: JwtPayload): AuthenticatedUser {
+    return {
+      userId: payload.sub,
+      role: payload.role,
+    }
+  }
+}
diff --git a/packages/server/src/auth/roles.decorator.ts b/packages/server/src/auth/roles.decorator.ts
new file mode 100644
index 0000000..9454222
--- /dev/null
+++ b/packages/server/src/auth/roles.decorator.ts
@@ -0,0 +1,6 @@
+import { SetMetadata } from '@nestjs/common'
+import { UserRole } from '@mp-pilates/shared'
+
+export const ROLES_KEY = 'roles'
+
+export const Roles = (...roles: UserRole[]) => SetMetadata(ROLES_KEY, roles)
diff --git a/packages/server/src/auth/roles.guard.ts b/packages/server/src/auth/roles.guard.ts
new file mode 100644
index 0000000..8ae2249
--- /dev/null
+++ b/packages/server/src/auth/roles.guard.ts
@@ -0,0 +1,33 @@
+import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common'
+import { Reflector } from '@nestjs/core'
+import { UserRole } from '@mp-pilates/shared'
+import { ROLES_KEY } from './roles.decorator'
+import { AuthenticatedUser } from './jwt.strategy'
+
+@Injectable()
+export class RolesGuard implements CanActivate {
+  constructor(private readonly reflector: Reflector) {}
+
+  canActivate(context: ExecutionContext): boolean {
+    const requiredRoles = this.reflector.getAllAndOverride<UserRole[]>(
+      ROLES_KEY,
+      [context.getHandler(), context.getClass()],
+    )
+
+    if (!requiredRoles || requiredRoles.length === 0) {
+      return true
+    }
+
+    const request = context.switchToHttp().getRequest<{
+      user?: AuthenticatedUser
+    }>()
+
+    const user = request.user
+
+    if (!user) {
+      return false
+    }
+
+    return requiredRoles.includes(user.role)
+  }
+}
diff --git a/packages/server/src/auth/wechat.service.ts b/packages/server/src/auth/wechat.service.ts
new file mode 100644
index 0000000..551ab8a
--- /dev/null
+++ b/packages/server/src/auth/wechat.service.ts
@@ -0,0 +1,107 @@
+import { Injectable, HttpException, HttpStatus } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
+import * as crypto from 'crypto'
+
+export interface Code2SessionResult {
+  openid: string
+  sessionKey: string
+  unionid?: string
+}
+
+export interface WechatPhoneInfo {
+  phoneNumber: string
+  purePhoneNumber: string
+  countryCode: string
+}
+
+@Injectable()
+export class WechatService {
+  private readonly appId: string
+  private readonly secret: string
+
+  constructor(private readonly configService: ConfigService) {
+    this.appId = this.configService.getOrThrow<string>('WX_APPID')
+    this.secret = this.configService.getOrThrow<string>('WX_SECRET')
+  }
+
+  async code2Session(code: string): Promise<Code2SessionResult> {
+    const url =
+      `https://api.weixin.qq.com/sns/jscode2session` +
+      `?appid=${this.appId}` +
+      `&secret=${this.secret}` +
+      `&js_code=${code}` +
+      `&grant_type=authorization_code`
+
+    const response = await fetch(url)
+
+    if (!response.ok) {
+      throw new HttpException(
+        'WeChat API request failed',
+        HttpStatus.BAD_GATEWAY,
+      )
+    }
+
+    const data = (await response.json()) as {
+      openid?: string
+      session_key?: string
+      unionid?: string
+      errcode?: number
+      errmsg?: string
+    }
+
+    if (data.errcode) {
+      throw new HttpException(
+        `WeChat login error: ${data.errmsg ?? data.errcode}`,
+        HttpStatus.UNAUTHORIZED,
+      )
+    }
+
+    if (!data.openid || !data.session_key) {
+      throw new HttpException(
+        'Invalid response from WeChat API',
+        HttpStatus.BAD_GATEWAY,
+      )
+    }
+
+    return {
+      openid: data.openid,
+      sessionKey: data.session_key,
+      ...(data.unionid !== undefined && { unionid: data.unionid }),
+    }
+  }
+
+  decryptData(
+    sessionKey: string,
+    encryptedData: string,
+    iv: string,
+  ): WechatPhoneInfo {
+    const sessionKeyBuffer = Buffer.from(sessionKey, 'base64')
+    const encryptedDataBuffer = Buffer.from(encryptedData, 'base64')
+    const ivBuffer = Buffer.from(iv, 'base64')
+
+    const decipher = crypto.createDecipheriv(
+      'aes-128-cbc',
+      sessionKeyBuffer,
+      ivBuffer,
+    )
+    decipher.setAutoPadding(true)
+
+    const decryptedBuffer = Buffer.concat([
+      decipher.update(encryptedDataBuffer),
+      decipher.final(),
+    ])
+
+    const decryptedText = decryptedBuffer.toString('utf8')
+    const decryptedData = JSON.parse(decryptedText) as {
+      phoneNumber: string
+      purePhoneNumber: string
+      countryCode: string
+    }
+
+    return {
+      phoneNumber: decryptedData.phoneNumber,
+      purePhoneNumber: decryptedData.purePhoneNumber,
+      countryCode: decryptedData.countryCode,
+    }
+  }
+}
diff --git a/packages/server/src/common/decorators/current-user.decorator.ts b/packages/server/src/common/decorators/current-user.decorator.ts
new file mode 100644
index 0000000..5b286b3
--- /dev/null
+++ b/packages/server/src/common/decorators/current-user.decorator.ts
@@ -0,0 +1,17 @@
+import { createParamDecorator, ExecutionContext } from '@nestjs/common'
+
+/**
+ * Extract a field from the JWT payload attached by JwtAuthGuard.
+ * JWT payload shape: { sub: userId, role: userRole }
+ *
+ * Usage:
+ *   @CurrentUser('sub') userId: string   ← specific field
+ *   @CurrentUser() user: JwtPayload      ← full payload
+ */
+export const CurrentUser = createParamDecorator(
+  (data: string | undefined, ctx: ExecutionContext) => {
+    const request = ctx.switchToHttp().getRequest()
+    const user = request.user as Record<string, unknown> | undefined
+    return data ? user?.[data] : user
+  },
+)
diff --git a/packages/server/src/studio/__tests__/studio.service.spec.ts b/packages/server/src/studio/__tests__/studio.service.spec.ts
new file mode 100644
index 0000000..3b11f7b
--- /dev/null
+++ b/packages/server/src/studio/__tests__/studio.service.spec.ts
@@ -0,0 +1,109 @@
+import { Test, TestingModule } from '@nestjs/testing'
+import { StudioService } from '../studio.service'
+import { PrismaService } from '../../prisma/prisma.service'
+import { UpdateStudioDto } from '../dto/update-studio.dto'
+
+const mockStudioConfig = {
+  id: 'test-id-001',
+  name: '普拉提工作室',
+  logo: null,
+  bannerUrl: null,
+  address: '',
+  phone: '',
+  latitude: null,
+  longitude: null,
+  cancelHoursLimit: 2,
+  photos: [],
+  updatedAt: new Date('2024-01-01T00:00:00Z'),
+}
+
+const mockPrismaService = {
+  studioConfig: {
+    findFirst: jest.fn(),
+    create: jest.fn(),
+    update: jest.fn(),
+  },
+}
+
+describe('StudioService', () => {
+  let service: StudioService
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        StudioService,
+        { provide: PrismaService, useValue: mockPrismaService },
+      ],
+    }).compile()
+
+    service = module.get<StudioService>(StudioService)
+    jest.clearAllMocks()
+  })
+
+  describe('getInfo()', () => {
+    it('should return existing config when one exists', async () => {
+      mockPrismaService.studioConfig.findFirst.mockResolvedValue(mockStudioConfig)
+
+      const result = await service.getInfo()
+
+      expect(result).toEqual(mockStudioConfig)
+      expect(mockPrismaService.studioConfig.findFirst).toHaveBeenCalledTimes(1)
+      expect(mockPrismaService.studioConfig.create).not.toHaveBeenCalled()
+    })
+
+    it('should create and return a default config when none exists', async () => {
+      const defaultConfig = { ...mockStudioConfig, name: '普拉提工作室' }
+      mockPrismaService.studioConfig.findFirst.mockResolvedValue(null)
+      mockPrismaService.studioConfig.create.mockResolvedValue(defaultConfig)
+
+      const result = await service.getInfo()
+
+      expect(result).toEqual(defaultConfig)
+      expect(mockPrismaService.studioConfig.findFirst).toHaveBeenCalledTimes(1)
+      expect(mockPrismaService.studioConfig.create).toHaveBeenCalledWith({
+        data: { name: '普拉提工作室' },
+      })
+    })
+  })
+
+  describe('updateInfo()', () => {
+    it('should update and return a new config object with changes applied', async () => {
+      const dto: UpdateStudioDto = {
+        name: 'New Studio Name',
+        address: '123 Main St',
+        cancelHoursLimit: 4,
+      }
+      const updatedConfig = {
+        ...mockStudioConfig,
+        name: dto.name!,
+        address: dto.address!,
+        cancelHoursLimit: dto.cancelHoursLimit!,
+        updatedAt: new Date(),
+      }
+
+      mockPrismaService.studioConfig.findFirst.mockResolvedValue(mockStudioConfig)
+      mockPrismaService.studioConfig.update.mockResolvedValue(updatedConfig)
+
+      const result = await service.updateInfo(dto)
+
+      expect(result).toEqual(updatedConfig)
+      expect(mockPrismaService.studioConfig.update).toHaveBeenCalledWith({
+        where: { id: mockStudioConfig.id },
+        data: { ...dto },
+      })
+    })
+
+    it('should return a new object reference (immutable)', async () => {
+      const dto: UpdateStudioDto = { name: 'Updated Name' }
+      const updatedConfig = { ...mockStudioConfig, name: 'Updated Name' }
+
+      mockPrismaService.studioConfig.findFirst.mockResolvedValue(mockStudioConfig)
+      mockPrismaService.studioConfig.update.mockResolvedValue(updatedConfig)
+
+      const result = await service.updateInfo(dto)
+
+      expect(result).not.toBe(updatedConfig)
+      expect(result).toEqual(updatedConfig)
+    })
+  })
+})
diff --git a/packages/server/src/studio/dto/update-studio.dto.ts b/packages/server/src/studio/dto/update-studio.dto.ts
new file mode 100644
index 0000000..1a85db3
--- /dev/null
+++ b/packages/server/src/studio/dto/update-studio.dto.ts
@@ -0,0 +1,53 @@
+import {
+  IsArray,
+  IsNumber,
+  IsOptional,
+  IsString,
+  IsUrl,
+  Max,
+  Min,
+} from 'class-validator'
+
+export class UpdateStudioDto {
+  @IsOptional()
+  @IsString()
+  name?: string
+
+  @IsOptional()
+  @IsString()
+  logo?: string
+
+  @IsOptional()
+  @IsString()
+  bannerUrl?: string
+
+  @IsOptional()
+  @IsString()
+  address?: string
+
+  @IsOptional()
+  @IsString()
+  phone?: string
+
+  @IsOptional()
+  @IsNumber()
+  @Min(-90)
+  @Max(90)
+  latitude?: number
+
+  @IsOptional()
+  @IsNumber()
+  @Min(-180)
+  @Max(180)
+  longitude?: number
+
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  cancelHoursLimit?: number
+
+  @IsOptional()
+  @IsArray()
+  @IsString({ each: true })
+  photos?: string[]
+}
diff --git a/packages/server/src/studio/studio.controller.ts b/packages/server/src/studio/studio.controller.ts
new file mode 100644
index 0000000..faeaca9
--- /dev/null
+++ b/packages/server/src/studio/studio.controller.ts
@@ -0,0 +1,30 @@
+import {
+  Body,
+  Controller,
+  Get,
+  Put,
+  UseGuards,
+} from '@nestjs/common'
+import { UserRole } from '@mp-pilates/shared'
+import { JwtAuthGuard } from '../auth/jwt-auth.guard'
+import { Roles } from '../auth/roles.decorator'
+import { RolesGuard } from '../auth/roles.guard'
+import { UpdateStudioDto } from './dto/update-studio.dto'
+import { StudioService } from './studio.service'
+
+@Controller()
+export class StudioController {
+  constructor(private readonly studioService: StudioService) {}
+
+  @Get('studio/info')
+  getInfo() {
+    return this.studioService.getInfo()
+  }
+
+  @Put('admin/studio/info')
+  @UseGuards(JwtAuthGuard, RolesGuard)
+  @Roles(UserRole.ADMIN)
+  updateInfo(@Body() dto: UpdateStudioDto) {
+    return this.studioService.updateInfo(dto)
+  }
+}
diff --git a/packages/server/src/studio/studio.module.ts b/packages/server/src/studio/studio.module.ts
new file mode 100644
index 0000000..e297b57
--- /dev/null
+++ b/packages/server/src/studio/studio.module.ts
@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common'
+import { StudioController } from './studio.controller'
+import { StudioService } from './studio.service'
+
+@Module({
+  controllers: [StudioController],
+  providers: [StudioService],
+  exports: [StudioService],
+})
+export class StudioModule {}
diff --git a/packages/server/src/studio/studio.service.ts b/packages/server/src/studio/studio.service.ts
new file mode 100644
index 0000000..68c6604
--- /dev/null
+++ b/packages/server/src/studio/studio.service.ts
@@ -0,0 +1,34 @@
+import { Injectable } from '@nestjs/common'
+import { StudioConfig } from '@prisma/client'
+import { PrismaService } from '../prisma/prisma.service'
+import { UpdateStudioDto } from './dto/update-studio.dto'
+
+@Injectable()
+export class StudioService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  async getInfo(): Promise<StudioConfig> {
+    const existing = await this.prisma.studioConfig.findFirst()
+
+    if (existing) {
+      return existing
+    }
+
+    return this.prisma.studioConfig.create({
+      data: {
+        name: '普拉提工作室',
+      },
+    })
+  }
+
+  async updateInfo(dto: UpdateStudioDto): Promise<StudioConfig> {
+    const existing = await this.getInfo()
+
+    const updated = await this.prisma.studioConfig.update({
+      where: { id: existing.id },
+      data: { ...dto },
+    })
+
+    return { ...updated }
+  }
+}
diff --git a/packages/server/src/user/__tests__/user.service.spec.ts b/packages/server/src/user/__tests__/user.service.spec.ts
new file mode 100644
index 0000000..81fec5e
--- /dev/null
+++ b/packages/server/src/user/__tests__/user.service.spec.ts
@@ -0,0 +1,275 @@
+import { Test, TestingModule } from '@nestjs/testing'
+import { NotFoundException } from '@nestjs/common'
+import { UserService } from '../user.service'
+import { PrismaService } from '../../prisma/prisma.service'
+import { MembershipStatus, BookingStatus, UserRole } from '@mp-pilates/shared'
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+const makeUser = (overrides: Record<string, unknown> = {}) => ({
+  id: 'user-1',
+  openid: 'openid-1',
+  unionid: null,
+  phone: '13800000000',
+  nickname: 'Alice',
+  avatarUrl: 'https://example.com/avatar.png',
+  role: UserRole.MEMBER,
+  createdAt: new Date('2024-01-01T00:00:00Z'),
+  updatedAt: new Date('2024-01-01T00:00:00Z'),
+  _count: { memberships: 2 },
+  ...overrides,
+})
+
+const makeBooking = (
+  date: Date,
+  startTime: string,
+  endTime: string,
+  status: BookingStatus = BookingStatus.COMPLETED,
+) => ({
+  id: `booking-${Math.random()}`,
+  userId: 'user-1',
+  timeSlotId: `slot-${Math.random()}`,
+  membershipId: `membership-${Math.random()}`,
+  status,
+  cancelledAt: null,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  timeSlot: { date, startTime, endTime },
+})
+
+// ---------------------------------------------------------------------------
+// Mock PrismaService
+// ---------------------------------------------------------------------------
+
+const mockPrisma = {
+  user: {
+    findUnique: jest.fn(),
+    update: jest.fn(),
+  },
+  booking: {
+    findMany: jest.fn(),
+  },
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+describe('UserService', () => {
+  let service: UserService
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        UserService,
+        { provide: PrismaService, useValue: mockPrisma },
+      ],
+    }).compile()
+
+    service = module.get<UserService>(UserService)
+    jest.clearAllMocks()
+  })
+
+  // -------------------------------------------------------------------------
+  // getProfile
+  // -------------------------------------------------------------------------
+
+  describe('getProfile', () => {
+    it('returns a UserProfileResponse with activeMembershipCount', async () => {
+      const user = makeUser({ _count: { memberships: 3 } })
+      mockPrisma.user.findUnique.mockResolvedValue(user)
+
+      const result = await service.getProfile('user-1')
+
+      expect(mockPrisma.user.findUnique).toHaveBeenCalledWith({
+        where: { id: 'user-1' },
+        include: {
+          _count: {
+            select: {
+              memberships: { where: { status: MembershipStatus.ACTIVE } },
+            },
+          },
+        },
+      })
+
+      expect(result).toEqual({
+        id: 'user-1',
+        phone: '13800000000',
+        nickname: 'Alice',
+        avatarUrl: 'https://example.com/avatar.png',
+        role: UserRole.MEMBER,
+        activeMembershipCount: 3,
+        createdAt: new Date('2024-01-01T00:00:00Z').toISOString(),
+      })
+    })
+
+    it('throws NotFoundException when user does not exist', async () => {
+      mockPrisma.user.findUnique.mockResolvedValue(null)
+
+      await expect(service.getProfile('unknown')).rejects.toThrow(NotFoundException)
+    })
+  })
+
+  // -------------------------------------------------------------------------
+  // updateProfile
+  // -------------------------------------------------------------------------
+
+  describe('updateProfile', () => {
+    it('updates nickname and avatarUrl, returns new UserProfileResponse', async () => {
+      const updated = makeUser({
+        nickname: 'Bob',
+        avatarUrl: 'https://example.com/new.png',
+        _count: { memberships: 1 },
+      })
+      mockPrisma.user.update.mockResolvedValue(updated)
+
+      const result = await service.updateProfile('user-1', {
+        nickname: 'Bob',
+        avatarUrl: 'https://example.com/new.png',
+      })
+
+      expect(mockPrisma.user.update).toHaveBeenCalledWith({
+        where: { id: 'user-1' },
+        data: { nickname: 'Bob', avatarUrl: 'https://example.com/new.png' },
+        include: {
+          _count: {
+            select: {
+              memberships: { where: { status: MembershipStatus.ACTIVE } },
+            },
+          },
+        },
+      })
+
+      expect(result.nickname).toBe('Bob')
+      expect(result.avatarUrl).toBe('https://example.com/new.png')
+      expect(result.activeMembershipCount).toBe(1)
+    })
+
+    it('only includes provided fields in the update payload', async () => {
+      const updated = makeUser({ nickname: 'Charlie', _count: { memberships: 0 } })
+      mockPrisma.user.update.mockResolvedValue(updated)
+
+      await service.updateProfile('user-1', { nickname: 'Charlie' })
+
+      const callArgs = mockPrisma.user.update.mock.calls[0][0]
+      expect(callArgs.data).toEqual({ nickname: 'Charlie' })
+      expect(callArgs.data.avatarUrl).toBeUndefined()
+    })
+
+    it('returns an immutable snapshot — the original dto is not mutated', async () => {
+      const updated = makeUser({ _count: { memberships: 0 } })
+      mockPrisma.user.update.mockResolvedValue(updated)
+
+      const dto = { nickname: 'Dave' }
+      const originalDto = { ...dto }
+
+      await service.updateProfile('user-1', dto)
+
+      expect(dto).toEqual(originalDto)
+    })
+  })
+
+  // -------------------------------------------------------------------------
+  // getStats
+  // -------------------------------------------------------------------------
+
+  describe('getStats', () => {
+    /**
+     * Build a date in the *current* month so the month-filter logic works
+     * regardless of when the test is run.
+     */
+    const thisYear = new Date().getFullYear()
+    const thisMonth = new Date().getMonth()
+
+    const dateInMonth = (day: number) => new Date(thisYear, thisMonth, day)
+    const dateLastMonth = new Date(thisYear, thisMonth - 1, 15)
+
+    it('returns zeroed stats when there are no completed bookings', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([])
+
+      const result = await service.getStats('user-1')
+
+      expect(result).toEqual({
+        totalBookings: 0,
+        totalDays: 0,
+        monthBookings: 0,
+        monthDays: 0,
+        monthHours: 0,
+      })
+    })
+
+    it('counts all completed bookings for totalBookings', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([
+        makeBooking(dateInMonth(1), '09:00', '10:00'),
+        makeBooking(dateLastMonth, '09:00', '10:00'),
+      ])
+
+      const result = await service.getStats('user-1')
+
+      expect(result.totalBookings).toBe(2)
+    })
+
+    it('counts distinct dates for totalDays', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([
+        makeBooking(dateInMonth(1), '09:00', '10:00'),
+        makeBooking(dateInMonth(1), '11:00', '12:00'), // same day → still 1 distinct day
+        makeBooking(dateLastMonth, '09:00', '10:00'),
+      ])
+
+      const result = await service.getStats('user-1')
+
+      expect(result.totalDays).toBe(2) // day-in-month(1) + last-month-day
+    })
+
+    it('only counts this-month bookings in monthBookings', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([
+        makeBooking(dateInMonth(5), '09:00', '10:00'),
+        makeBooking(dateInMonth(10), '09:00', '10:00'),
+        makeBooking(dateLastMonth, '09:00', '10:00'), // excluded
+      ])
+
+      const result = await service.getStats('user-1')
+
+      expect(result.monthBookings).toBe(2)
+    })
+
+    it('counts distinct this-month dates for monthDays', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([
+        makeBooking(dateInMonth(3), '09:00', '10:00'),
+        makeBooking(dateInMonth(3), '11:00', '12:00'), // same day
+        makeBooking(dateInMonth(7), '09:00', '10:00'),
+        makeBooking(dateLastMonth, '09:00', '10:00'), // excluded
+      ])
+
+      const result = await service.getStats('user-1')
+
+      expect(result.monthDays).toBe(2)
+    })
+
+    it('sums hours for monthHours from startTime/endTime', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([
+        makeBooking(dateInMonth(1), '09:00', '10:00'), // 1 h
+        makeBooking(dateInMonth(2), '14:00', '15:30'), // 1.5 h
+        makeBooking(dateLastMonth, '09:00', '10:00'),  // excluded
+      ])
+
+      const result = await service.getStats('user-1')
+
+      expect(result.monthHours).toBeCloseTo(2.5)
+    })
+
+    it('queries only COMPLETED bookings for this user', async () => {
+      mockPrisma.booking.findMany.mockResolvedValue([])
+
+      await service.getStats('user-1')
+
+      expect(mockPrisma.booking.findMany).toHaveBeenCalledWith(
+        expect.objectContaining({
+          where: { userId: 'user-1', status: BookingStatus.COMPLETED },
+        }),
+      )
+    })
+  })
+})
diff --git a/packages/server/src/user/dto/update-profile.dto.ts b/packages/server/src/user/dto/update-profile.dto.ts
new file mode 100644
index 0000000..22fed44
--- /dev/null
+++ b/packages/server/src/user/dto/update-profile.dto.ts
@@ -0,0 +1,13 @@
+import { IsOptional, IsString, MaxLength } from 'class-validator'
+
+export class UpdateProfileDto {
+  @IsOptional()
+  @IsString()
+  @MaxLength(32)
+  readonly nickname?: string
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(512)
+  readonly avatarUrl?: string
+}
diff --git a/packages/server/src/user/user.controller.ts b/packages/server/src/user/user.controller.ts
new file mode 100644
index 0000000..9f21e95
--- /dev/null
+++ b/packages/server/src/user/user.controller.ts
@@ -0,0 +1,35 @@
+import {
+  Controller,
+  Get,
+  Put,
+  Body,
+  UseGuards,
+} from '@nestjs/common'
+import { JwtAuthGuard } from '../auth/jwt-auth.guard'
+import { CurrentUser } from '../common/decorators/current-user.decorator'
+import { UserService } from './user.service'
+import { UpdateProfileDto } from './dto/update-profile.dto'
+
+@UseGuards(JwtAuthGuard)
+@Controller('user')
+export class UserController {
+  constructor(private readonly userService: UserService) {}
+
+  @Get('profile')
+  getProfile(@CurrentUser('sub') userId: string) {
+    return this.userService.getProfile(userId)
+  }
+
+  @Put('profile')
+  updateProfile(
+    @CurrentUser('sub') userId: string,
+    @Body() dto: UpdateProfileDto,
+  ) {
+    return this.userService.updateProfile(userId, dto)
+  }
+
+  @Get('stats')
+  getStats(@CurrentUser('sub') userId: string) {
+    return this.userService.getStats(userId)
+  }
+}
diff --git a/packages/server/src/user/user.module.ts b/packages/server/src/user/user.module.ts
new file mode 100644
index 0000000..b2060ee
--- /dev/null
+++ b/packages/server/src/user/user.module.ts
@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common'
+import { UserController } from './user.controller'
+import { UserService } from './user.service'
+
+@Module({
+  controllers: [UserController],
+  providers: [UserService],
+  exports: [UserService],
+})
+export class UserModule {}
diff --git a/packages/server/src/user/user.service.ts b/packages/server/src/user/user.service.ts
new file mode 100644
index 0000000..e9b039c
--- /dev/null
+++ b/packages/server/src/user/user.service.ts
@@ -0,0 +1,120 @@
+import { Injectable, NotFoundException } from '@nestjs/common'
+import { MembershipStatus, BookingStatus, UserRole } from '@mp-pilates/shared'
+import { PrismaService } from '../prisma/prisma.service'
+import type { UserProfileResponse, UserStatsResponse } from '@mp-pilates/shared'
+
+@Injectable()
+export class UserService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  async getProfile(userId: string): Promise<UserProfileResponse> {
+    const user = await this.prisma.user.findUnique({
+      where: { id: userId },
+      include: {
+        _count: {
+          select: {
+            memberships: {
+              where: { status: MembershipStatus.ACTIVE },
+            },
+          },
+        },
+      },
+    })
+
+    if (!user) {
+      throw new NotFoundException('User not found')
+    }
+
+    return {
+      id: user.id,
+      phone: user.phone,
+      nickname: user.nickname,
+      avatarUrl: user.avatarUrl,
+      role: user.role as UserRole,
+      activeMembershipCount: user._count.memberships,
+      createdAt: user.createdAt.toISOString(),
+    }
+  }
+
+  async updateProfile(
+    userId: string,
+    dto: { nickname?: string; avatarUrl?: string },
+  ): Promise<UserProfileResponse> {
+    const updated = await this.prisma.user.update({
+      where: { id: userId },
+      data: {
+        ...(dto.nickname !== undefined && { nickname: dto.nickname }),
+        ...(dto.avatarUrl !== undefined && { avatarUrl: dto.avatarUrl }),
+      },
+      include: {
+        _count: {
+          select: {
+            memberships: {
+              where: { status: MembershipStatus.ACTIVE },
+            },
+          },
+        },
+      },
+    })
+
+    return {
+      id: updated.id,
+      phone: updated.phone,
+      nickname: updated.nickname,
+      avatarUrl: updated.avatarUrl,
+      role: updated.role as UserRole,
+      activeMembershipCount: updated._count.memberships,
+      createdAt: updated.createdAt.toISOString(),
+    }
+  }
+
+  async getStats(userId: string): Promise<UserStatsResponse> {
+    const completedBookings = await this.prisma.booking.findMany({
+      where: {
+        userId,
+        status: BookingStatus.COMPLETED,
+      },
+      include: {
+        timeSlot: {
+          select: {
+            date: true,
+            startTime: true,
+            endTime: true,
+          },
+        },
+      },
+    })
+
+    const now = new Date()
+    const monthStart = new Date(now.getFullYear(), now.getMonth(), 1)
+    const monthEnd = new Date(now.getFullYear(), now.getMonth() + 1, 0, 23, 59, 59, 999)
+
+    const monthBookings = completedBookings.filter((b) => {
+      const slotDate = new Date(b.timeSlot.date)
+      return slotDate >= monthStart && slotDate <= monthEnd
+    })
+
+    const totalDays = new Set(
+      completedBookings.map((b) => b.timeSlot.date.toISOString().split('T')[0]),
+    ).size
+
+    const monthDays = new Set(
+      monthBookings.map((b) => b.timeSlot.date.toISOString().split('T')[0]),
+    ).size
+
+    const monthHours = monthBookings.reduce((sum, b) => {
+      const [startH, startM] = b.timeSlot.startTime.split(':').map(Number)
+      const [endH, endM] = b.timeSlot.endTime.split(':').map(Number)
+      const durationMinutes = endH * 60 + endM - (startH * 60 + startM)
+      return sum + durationMinutes / 60
+    }, 0)
+
+    return {
+      totalBookings: completedBookings.length,
+      totalDays,
+      monthBookings: monthBookings.length,
+      monthDays,
+      monthHours,
+    }
+  }
+}