# PyPI (Python Infrastructure): PyPI Partial Outage

- Impact (vendor’s label): major
- Status: resolved
- Started: 2025-05-24 23:37 UTC · Resolved: 2025-05-27 12:53 UTC · Duration: 3 d
- Updates: 6 · Affected components: pypi.org - Backends, PyPI - pypi.org - Backends
- [Vendor status page: https://stspg.io/dcxkgkkx6sj8](https://stspg.io/dcxkgkkx6sj8)
- [Company: PyPI (Python Infrastructure)](https://rewindex.com/company/pypi.md)

## Timeline of updates

- **investigating** 2025-05-24 22:57 UTC: We are working to investigate a partial outage in the PyPI backends.
- **identified** 2025-05-24 23:11 UTC: We have identified a large increase in CDN cache misses causing excess load on our backends. We are working to determine the reason for this increase.
- **identified** 2025-05-24 23:37 UTC: We have identified a flood of requests from a cluster using the \`python-requests/2.32.3\` User-Agent, and attempting to hit all JSON project/releasese en masse. This causes excessive cache misses, which are overwhelming our backends. A temporary block has been put in place.
- **monitoring** 2025-05-24 23:54 UTC: Our block is in place and systems are stable, but we are not satisfied with having to block such a generic user-agent. If you are aware of a system that began a mass crawl of PyPI's JSON release endpoints starting at around 22:05 UTC 2025-05-25, please contact admin@pypi.org.
- **monitoring** 2025-05-25 12:16 UTC: We have removed the temporary block and are continuing to monitor.
- **resolved** 2025-05-27 12:53 UTC: We have not seen a return of the traffic that caused this incident after removing the temporary block. We will open a new incident if we need to take action again.

## Rewindex changes for this incident

- 2025-05-24 23:37 UTC: [Major incident: PyPI Partial Outage](https://rewindex.com/change/i7ff07a3ce707ac.md)


---
Canonical: https://rewindex.com/company/pypi/incidents/wtqw8mxcg3j1 · Markdown: https://rewindex.com/company/pypi/incidents/wtqw8mxcg3j1.md · JSON: https://rewindex.com/api/v1/companies/pypi/incidents/wtqw8mxcg3j1 · Generated 2026-10-20T00:14:19.133Z