# fastapi.exceptions.ResponseValidationError: Response model validation failed: field 'email' is not a valid email address

- **ID:** `python/fastapi-response-model-validation`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

FastAPI响应数据不符合响应模型中的验证规则

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.x | active | — | — |

## Workarounds

1. **确保数据符合模型验证规则** (95% success)
   ```
   from pydantic import EmailStr
class UserOut(BaseModel):
    email: EmailStr
user = UserOut(email='valid@example.com')
   ```
2. **使用response_model_exclude_unset选项** (85% success)
   ```
   @app.get('/user', response_model=UserOut, response_model_exclude_unset=True)
   ```

## Dead Ends

- **在响应模型中移除验证规则** — 移除验证会降低数据质量 (50% fail)
- **使用try-except捕获响应错误** — 验证在响应发送前执行，无法在应用层捕获 (40% fail)