# RuntimeError: No application configured

- **ID:** `python/starlette-runtime-error-no-app`
- **Domain:** python
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Starlette application instance is not created or not passed to the ASGI server.

## Version Compatibility

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

## Workarounds

1. **Define a Starlette app instance and pass it to uvicorn.** (90% success)
   ```
   from starlette.applications import Starlette
app = Starlette()
# Then run: uvicorn main:app
   ```
2. **Ensure the server command references the correct module and app variable.** (85% success)
   ```
   uvicorn mymodule:app --reload
   ```

## Dead Ends

- **Trying to run the server without defining the app variable.** — The server expects an ASGI application object; without it, it fails. (80% fail)
- **Using a wrong file name in the server command.** — The server cannot find the app if the module path is incorrect. (70% fail)