# RuntimeError: Form data requires "python-multipart" to be installed.

- **ID:** `python/fastapi-form-data-missing-python-multipart`
- **Domain:** python
- **Category:** install_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A route used Form or File parameters but the python-multipart package was not installed in the environment.

## Version Compatibility

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

## Workarounds

1. **** (98% success)
   ```
   pip install python-multipart
   ```
2. **** (95% success)
   ```
   echo 'python-multipart>=0.0.9' >> requirements.txt
pip install -r requirements.txt
   ```

## Dead Ends

- **** — Body expects JSON; form-encoded clients receive 422 errors. (80% fail)
- **** — There is no stdlib multipart parser; import fails. (90% fail)