diff --git a/apps/api/app/api/routes/auth.py b/apps/api/app/api/routes/auth.py
index b3765ec19..af31d8e35 100755
--- a/apps/api/app/api/routes/auth.py
+++ b/apps/api/app/api/routes/auth.py
@@ -6,13 +6,14 @@ app.dependencies and authentication behavior lives in application use cases.
 """
 
 import logging
+import os
 from typing import Optional
 
 import jwt
 from app.auth import AuthenticatedUser, blacklist_token, get_current_user
 from app.config import settings
 from app.dependencies import get_auth_email_service, get_auth_session_store, get_user_repository
-from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi import APIRouter, Depends, Header, HTTPException, status
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from pydantic import BaseModel, EmailStr
 
@@ -284,3 +285,99 @@ def _translate_auth_error(error: str | None) -> str:
         "Display name is required": "显示名称不能为空",
     }
     return translations.get(error or "", error or "注册失败")
+
+
+class WechatSyncRequest(BaseModel):
+    openid: str
+    unionid: Optional[str] = None
+    nickname: Optional[str] = None
+    avatar_url: Optional[str] = None
+    source: str = "miniapp"
+
+
+class WechatSyncResponse(BaseModel):
+    access_token: str
+    token: str
+    refresh_token: str
+    user_id: str
+    user: dict
+    user_info: dict
+    is_new_user: bool
+    expires_in: int
+
+
+def _get_internal_api_keys() -> list[str]:
+    """获取内部 API Key 列表
+
+    优先级:
+    1. INTERNAL_API_KEYS 环境变量
+    2. /app/generated/internal_api_keys.txt 文件 (volume 持久化)
+    """
+    env_keys = os.environ.get("INTERNAL_API_KEYS", "")
+    if env_keys:
+        return [k.strip() for k in env_keys.split(",") if k.strip()]
+
+    # 从持久化文件读取
+    try:
+        with open("/app/generated/internal_api_keys.txt", "r") as f:
+            content = f.read().strip()
+            if content:
+                return [k.strip() for k in content.split(",") if k.strip()]
+    except Exception:
+        pass
+
+    return []
+
+
+def _verify_internal_api_key(x_api_key: str | None = Header(None)) -> bool:
+    """验证内部 API Key
+
+    - 已配置时：必须匹配 INTERNAL_API_KEYS 中的 key
+    - 未配置且非生产环境：放行（方便开发）
+    - 未配置且生产环境：拒绝
+    """
+    env = os.environ.get("APP_ENV", os.environ.get("ENV", "development")).lower()
+    key_list = _get_internal_api_keys()
+
+    if not key_list:
+        if env in ("production", "prod"):
+            raise HTTPException(status_code=401, detail="内部接口未配置 API Key")
+        return True
+
+    if x_api_key and x_api_key.strip() in key_list:
+        return True
+
+    raise HTTPException(status_code=401, detail="无效的 API Key")
+
+
+@router.post("/wechat-sync", response_model=WechatSyncResponse, include_in_schema=False)
+async def wechat_sync(
+    request: WechatSyncRequest,
+    user_repository: UserRepository = Depends(get_user_repository),
+    _: bool = Depends(_verify_internal_api_key),
+):
+    """
+    微信同步登录/注册（系统级内部接口）
+
+    由 BFF 层通过 API Key 调用，不直接面向终端用户。
+    根据 openid 查找或创建用户，返回 SaaS token。
+    """
+    from packages.application.auth.wechat_sync_use_case import (
+        WechatSyncRequest as UseCaseRequest,
+        WechatSyncUseCase,
+    )
+
+    use_case = WechatSyncUseCase(user_repository=user_repository)
+    use_case_request = UseCaseRequest(
+        openid=request.openid,
+        unionid=request.unionid,
+        nickname=request.nickname,
+        avatar_url=request.avatar_url,
+        source=request.source,
+    )
+
+    response, error = use_case.execute(use_case_request)
+    if error:
+        raise HTTPException(status_code=400, detail=error)
+
+    return WechatSyncResponse(**response.to_dict())
diff --git a/apps/api/app/api/routes/edit_templates.py b/apps/api/app/api/routes/edit_templates.py
index 108cc3d8e..0f9eb94c4 100644
--- a/apps/api/app/api/routes/edit_templates.py
+++ b/apps/api/app/api/routes/edit_templates.py
@@ -20,6 +20,7 @@ from app.auth import AuthenticatedUser, get_current_user
 from app.dependencies import get_db_session
 from app.services import EditTemplateService
 from fastapi import APIRouter, Depends, HTTPException, Query, status
+from fastapi.responses import Response
 from pydantic import BaseModel, Field
 from sqlalchemy.orm import Session
 
@@ -263,7 +264,7 @@ def delete_template(
     template_id: str,
     db: Session = Depends(get_db_session),
     current_user: AuthenticatedUser = Depends(get_current_user),
-) -> None:
+) -> Response:
     """删除模板（软删除 → 设为 inactive）"""
     _require_admin(current_user)
     svc = EditTemplateService(db)
@@ -275,3 +276,4 @@ def delete_template(
             detail=str(exc),
         )
     logger.info("删除模板(软删除): id=%s by user=%s", template_id, current_user.user.id)
+    return Response(status_code=204)
diff --git a/packages/adapters/sqlalchemy_impl/user_repository.py b/packages/adapters/sqlalchemy_impl/user_repository.py
index a5076583c..ab81133ce 100644
--- a/packages/adapters/sqlalchemy_impl/user_repository.py
+++ b/packages/adapters/sqlalchemy_impl/user_repository.py
@@ -33,6 +33,8 @@ class SQLAlchemyUserRepository(UserRepository):
         model.max_projects = user.max_projects
         model.max_storage_gb = user.max_storage_gb
         model.is_admin = user.is_admin
+        model.wechat_openid = user.wechat_openid
+        model.wechat_unionid = user.wechat_unionid
         model.created_at = user.created_at
 
         self.session.commit()
@@ -49,6 +51,16 @@ class SQLAlchemyUserRepository(UserRepository):
         model = self.session.query(UserModel).filter(UserModel.username == username.strip()).first()
         return self._to_entity(model)
 
+    def find_by_wechat_openid(self, openid: str) -> User | None:
+        model = self.session.query(UserModel).filter(UserModel.wechat_openid == openid.strip()).first()
+        return self._to_entity(model)
+
+    def find_by_wechat_unionid(self, unionid: str) -> User | None:
+        if not unionid or not unionid.strip():
+            return None
+        model = self.session.query(UserModel).filter(UserModel.wechat_unionid == unionid.strip()).first()
+        return self._to_entity(model)
+
     def find_by_verification_token(self, token: str) -> User | None:
         model = self.session.query(UserModel).filter(UserModel.email_verification_token == token).first()
         return self._to_entity(model)
@@ -87,5 +99,7 @@ class SQLAlchemyUserRepository(UserRepository):
             max_projects=model.max_projects or 3,
             max_storage_gb=model.max_storage_gb or 10,
             is_admin=model.is_admin or False,
+            wechat_openid=model.wechat_openid,
+            wechat_unionid=model.wechat_unionid,
             created_at=model.created_at,
         )
diff --git a/packages/application/auth/wechat_sync_use_case.py b/packages/application/auth/wechat_sync_use_case.py
new file mode 100644
index 000000000..0c699b207
--- /dev/null
+++ b/packages/application/auth/wechat_sync_use_case.py
@@ -0,0 +1,205 @@
+"""
+微信同步登录/注册 Use Case
+
+供 BFF 层调用的系统级接口：
+- 根据 openid 查找用户，找到则登录返回 token
+- 没找到则创建新用户并返回 token
+- 支持 unionid 跨应用关联
+"""
+
+import secrets
+from datetime import datetime, timedelta, timezone
+from typing import Optional
+from uuid import uuid4
+
+import jwt as pyjwt
+
+from packages.adapters.redis import get_session_store
+from packages.application.auth.jwt_service import jwt_service
+from packages.domain.entities import User
+
+
+class WechatSyncRequest:
+    """微信同步登录请求"""
+
+    def __init__(
+        self,
+        openid: str,
+        unionid: str = "",
+        nickname: str = "",
+        avatar_url: str = "",
+        source: str = "miniapp",
+    ):
+        self.openid = openid.strip()
+        self.unionid = unionid.strip() if unionid else ""
+        self.nickname = nickname or "微信用户"
+        self.avatar_url = avatar_url or ""
+        self.source = source
+
+
+class WechatSyncResponse:
+    """微信同步登录响应"""
+
+    def __init__(
+        self,
+        access_token: str,
+        refresh_token: str,
+        user_id: str,
+        nickname: str,
+        avatar_url: str,
+        is_new_user: bool,
+        expires_in: int,
+    ):
+        self.access_token = access_token
+        self.refresh_token = refresh_token
+        self.user_id = user_id
+        self.nickname = nickname
+        self.avatar_url = avatar_url
+        self.is_new_user = is_new_user
+        self.expires_in = expires_in
+
+    def to_dict(self) -> dict:
+        return {
+            "access_token": self.access_token,
+            "token": self.access_token,  # 兼容 BFF 层用 token 字段读取
+            "refresh_token": self.refresh_token,
+            "user_id": self.user_id,
+            "user": {
+                "id": self.user_id,
+                "nickname": self.nickname,
+                "avatar_url": self.avatar_url,
+                "display_name": self.nickname,
+            },
+            "user_info": {
+                "id": self.user_id,
+                "nickname": self.nickname,
+                "avatar_url": self.avatar_url,
+                "display_name": self.nickname,
+            },
+            "is_new_user": self.is_new_user,
+            "expires_in": self.expires_in,
+        }
+
+
+class WechatSyncUseCase:
+    """微信同步登录/注册用例
+
+    系统级接口，由 BFF 通过 API Key 调用。
+    职责：根据 openid 查找或创建用户，返回 SaaS token。
+    """
+
+    def __init__(self, user_repository, session_store=None, jwt_secret_key: str | None = None):
+        self.user_repository = user_repository
+        self.session_store = session_store or get_session_store()
+        self.jwt_secret_key = jwt_secret_key or jwt_service.config.SECRET_KEY
+
+    def execute(self, request: WechatSyncRequest) -> tuple[Optional[WechatSyncResponse], Optional[str]]:
+        """
+        执行微信同步登录/注册
+
+        Returns:
+            (响应对象, 错误信息) - 成功则错误信息为 None
+        """
+        try:
+            if not request.openid:
+                return None, "openid is required"
+
+            is_new_user = False
+
+            # 1. 按 openid 查找用户
+            user = self.user_repository.find_by_wechat_openid(request.openid)
+
+            # 2. 如果 openid 没找到，尝试 unionid
+            if not user and request.unionid:
+                user = self.user_repository.find_by_wechat_unionid(request.unionid)
+                if user:
+                    # 找到用户但 openid 为空，绑定一下当前 openid
+                    user.wechat_openid = request.openid
+                    self.user_repository.save(user)
+
+            # 3. 都没找到则创建新用户
+            if not user:
+                user = self._create_wechat_user(request)
+                is_new_user = True
+
+            # 4. 创建 session 并生成 token
+            session_id = secrets.token_urlsafe(16)
+            refresh_token = secrets.token_urlsafe(32)
+
+            now = datetime.now(timezone.utc)
+            access_token_payload = {
+                "sub": user.id,
+                "sid": session_id,
+                "type": "user_auth",
+                "iat": now,
+                "exp": now + timedelta(minutes=jwt_service.config.ACCESS_TOKEN_EXPIRE_MINUTES),
+            }
+            access_token = pyjwt.encode(
+                access_token_payload,
+                self.jwt_secret_key,
+                algorithm=jwt_service.config.ALGORITHM,
+            )
+
+            # 保存 session
+            self.session_store.save_session(
+                session_id=session_id,
+                user_id=user.id,
+                refresh_token=refresh_token,
+                device_info=f"wechat_{request.source}",
+                ip_address="bff_gateway",
+                expires_in_seconds=30 * 24 * 3600,  # 30 天
+            )
+
+            # 更新最后登录信息
+            user.last_login_at = now
+            user.last_login_ip = "bff_gateway"
+            self.user_repository.save(user)
+
+            response = WechatSyncResponse(
+                access_token=access_token,
+                refresh_token=refresh_token,
+                user_id=user.id,
+                nickname=user.display_name,
+                avatar_url="",  # SaaS 用户模型暂存头像，后续可扩展
+                is_new_user=is_new_user,
+                expires_in=jwt_service.config.ACCESS_TOKEN_EXPIRE_MINUTES * 60,
+            )
+
+            return response, None
+
+        except Exception as e:
+            return None, f"Internal error: {str(e)}"
+
+    def _create_wechat_user(self, request: WechatSyncRequest) -> User:
+        """创建微信用户"""
+        user_id = uuid4().hex
+
+        # 生成唯一名和邮箱（微信用户无真实邮箱，用 openid 生成占位）
+        safe_openid = request.openid.replace("-", "_")[:20]
+        username = f"wx_{safe_openid}"
+        email = f"{safe_openid}@wechat.local"
+
+        # 确保 username 唯一
+        suffix = 0
+        while self.user_repository.find_by_username(username):
+            suffix += 1
+            username = f"wx_{safe_openid}_{suffix}"
+
+        # 随机密码（微信用户不用密码登录）
+        random_password = secrets.token_urlsafe(32)
+        from packages.application.auth.password_hasher import password_hasher
+        password_hash = password_hasher.hash_password(random_password)
+
+        user = User(
+            id=user_id,
+            email=email,
+            username=username,
+            display_name=request.nickname or "微信用户",
+            password_hash=password_hash,
+            email_verified=True,  # 微信登录视为已验证
+            wechat_openid=request.openid,
+            wechat_unionid=request.unionid or None,
+        )
+
+        self.user_repository.save(user)
+        return user
diff --git a/packages/domain/entities.py b/packages/domain/entities.py
index e4fa37ae0..ef568686c 100644
--- a/packages/domain/entities.py
+++ b/packages/domain/entities.py
@@ -54,6 +54,11 @@ class User:
     used_storage_gb: float = 0.0
     # 管理员标识
     is_admin: bool = False
+
+    # 微信绑定
+    wechat_openid: str | None = None
+    wechat_unionid: str | None = None
+
     created_at: datetime = field(default_factory=lambda: datetime.now(timezone.utc))
 
 
diff --git a/packages/ports/user_repository.py b/packages/ports/user_repository.py
index 974ffd176..70c6d1124 100644
--- a/packages/ports/user_repository.py
+++ b/packages/ports/user_repository.py
@@ -41,6 +41,16 @@ class UserRepository(ABC):
         """根据密码重置令牌查找用户"""
         pass
 
+    @abstractmethod
+    def find_by_wechat_openid(self, openid: str) -> Optional[User]:
+        """根据微信 openid 查找用户"""
+        pass
+
+    @abstractmethod
+    def find_by_wechat_unionid(self, unionid: str) -> Optional[User]:
+        """根据微信 unionid 查找用户"""
+        pass
+
     @abstractmethod
     def delete(self, user_id: str) -> bool:
         """删除用户"""