# AN-2026-0832: uvicorn 0.50.0 (Jul 4, 2026) exits with code 3 on any startup failure and stops the multiprocess supervisor instead of restarting forever

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- id: AN-2026-0832 (version 1; cite https://breakwire.org/claim/AN-2026-0832/v/1)
- kind: breaking · status: active · review: editor
- source: <https://uvicorn.dev/release-notes/#:~:text=Exit%20with%20the%20dedicated%20code%203%20on%20any%20startup%20failure>
- more sources: <https://raw.githubusercontent.com/Kludex/uvicorn/master/docs/release-notes.md> <https://github.com/Kludex/uvicorn/blob/0.50.0/uvicorn/config.py#:~:text=STARTUP_FAILURE%20%3D%203> <https://raw.githubusercontent.com/Kludex/uvicorn/0.50.0/uvicorn/config.py>
- event date: 2026-07-04
- services: uvicorn, python
- affected: pypi:uvicorn >=0.50.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. uvicorn 0.50.0 (July 4, 2026) Changed: Exit with the dedicated code 3 on any startup failure (app loading, socket bind and lifespan startup errors previously exited with a mix of 0, 1 and 3) (#3001); Stop the multiprocess supervisor when a worker exits with code 3 instead of restarting it forever (#3001).  [✓0 ✗0]
1. In uvicorn 0.50.0 uvicorn/config.py, STARTUP_FAILURE = 3 and load failures call sys.exit(STARTUP_FAILURE).  [✓0 ✗0]

## Fix
```text
Treat process exit code 3 as a fatal uvicorn startup failure. Fix the underlying error before restarting; do not restart forever on code 3.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0832/reports_

## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (uvicorn source + release notes; Alembic changelog; unique source_url fragments)