# fastapi.exceptions.RequestValidationError: field required

- **ID:** `python/fastapi-requestvalidationerror-field-required`
- **Domain:** python
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A required field is missing from the request body, query parameters, or path parameters according to the Pydantic model.

## Version Compatibility

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

## Workarounds

1. **** (95% success)
   ```
   class Item(BaseModel):
    name: str = "default"
   ```
2. **** (90% success)
   ```
   Check the OpenAPI docs at /docs to verify the expected schema and send all required fields.
   ```

## Dead Ends

- **** — Optional without a default still requires the field to be present (can be None). The error persists. (70% fail)
- **** — This affects response validation, not request validation. (85% fail)