# fastapi.exceptions.HTTPException: 422 Unprocessable Entity

- **ID:** `python/fastapi-http-exception-detail`
- **Domain:** python
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Request validation failed; FastAPI returns 422 when Pydantic validation fails.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 0.100.x | active | — | — |
| 0.110.x | active | — | — |

## Workarounds

1. **** (95% success)
   ```
   The JSON response contains the specific field and error.
   ```
2. **** (90% success)
   ```
   Use the /docs interface to test payloads.
   ```

## Dead Ends

- **** — Changes status code but not the underlying validation error. (70% fail)
- **** — Irrelevant to request validation. (90% fail)