# 422 Unprocessable Entity: {"detail":[{"type":"missing","loc":["body","email"],"msg":"Field required"}]}

- **ID:** `python/fastapi-422-missing-body`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The client sent a JSON body missing a required field, or sent form data where JSON was expected, so Pydantic validation rejects the request.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 0.100+ | active | — | — |

## Workarounds

1. **** (90% success)
   ```
   class UserIn(BaseModel):
    email: EmailStr
    name: str = ''
   ```
2. **** (85% success)
   ```
   from fastapi import Form
@app.post('/u')
async def create(email: str = Form(...)): ...
   ```

## Dead Ends

- **** — Hides the real cause; clients still send invalid payloads and data is dropped. (85% fail)
- **** — Still required in Pydantic v2 unless a default is provided. (70% fail)