# werkzeug.exceptions.NotFound: 404 Not Found: The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

- **ID:** `python/flask-404-not-found-route`
- **Domain:** python
- **Category:** network_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The request URL does not match any registered route, often due to a missing url_prefix or trailing slash mismatch.

## Version Compatibility

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

## Workarounds

1. **** (90% success)
   ```
   for rule in app.url_map.iter_rules():
    print(rule, rule.methods)
   ```
2. **** (92% success)
   ```
   app.register_blueprint(api_bp, url_prefix='/api/v1')
   ```

## Dead Ends

- **** — Masks real routing bugs and breaks API semantics. (80% fail)
- **** — Only fixes trailing-slash cases, not missing prefixes. (75% fail)