# Firebase: Firebase Hosting returning unexpected 431 errors on some POST requests to Firebase Functions rewrites

> Firebase status incident “Firebase Hosting returning unexpected 431 errors on some POST requests to Firebase Functions rewrites” on 2025-12-20: impact minor (vendor’s label), 17 d, 2 update(s). Archived by Rewindex.

Canonical: https://rewindex.com/company/firebase/incidents/51yhjchdin3mc1542mkd
Last updated: 2026-01-06T20:30:00Z

- Impact (vendor’s label): minor
- Status: resolved
- Started: 2025-12-20 17:00 UTC · Resolved: 2026-01-06 20:30 UTC · Duration: 17 d
- Updates: 2 · Affected components: Hosting
- [Vendor status page: https://status.firebase.google.com/incidents/51YhJchdiN3Mc1542MkD](https://status.firebase.google.com/incidents/51YhJchdiN3Mc1542MkD)
- [Company: Firebase](https://rewindex.com/company/firebase.md)

## Timeline of updates

- **service disruption** 2026-01-06 17:34 UTC: POST requests against Firebase Hosting Sites with rewrites to Firebase Fuctions can occasionally return unexpected 431 errors.
- **resolved** 2026-01-06 19:29 UTC: The Firebase Hosting team is currently rolling out a fix. It should be available globally within a few hours.

## Cite this

Status incident (vendor impact label: minor) posted by Firebase, started 2025-12-20 17:00 UTC, resolved after 17 d, 2 update(s).

- Canonical URL: https://rewindex.com/company/firebase/incidents/51yhjchdin3mc1542mkd
- Citation: Firebase, “Firebase Hosting returning unexpected 431 errors on some POST requests to Firebase Functions rewrites” (2025-12-20 17:00 UTC). Archived by Rewindex: https://rewindex.com/company/firebase/incidents/51yhjchdin3mc1542mkd (CC BY 4.0).
- Markdown link: `[Firebase: Firebase Hosting returning unexpected 431 errors on some POST requests to Firebase Functions rewrites (2025-12-20)](https://rewindex.com/company/firebase/incidents/51yhjchdin3mc1542mkd)`


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Canonical: https://rewindex.com/company/firebase/incidents/51yhjchdin3mc1542mkd · Markdown: https://rewindex.com/company/firebase/incidents/51yhjchdin3mc1542mkd.md · JSON: https://rewindex.com/api/v1/companies/firebase/incidents/51yhjchdin3mc1542mkd · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-11-04T16:07:53.390Z