On May 28, 2026, between 19:07 UTC and 19:16 UTC, multiple GitHub services experienced elevated error rates. This was due to a change that was partially deployed to an authentication service, causing errors for dependent services including the web experience, REST API, Git operations, and GitHub Actions. At peak impact, 10% of GitHub Actions runs failed to queue or encountered errors while downloading actions. We mitigated the incident by rolling back the change. We are expanding test coverage and improving our deployment validation process to prevent recurrence of this issue in the future.
On May 19, 2026, between 05:30 UTC and 14:50 UTC, some Copilot users experienced failures when using code completions, chat sessions, and cloud agent sessions. At peak impact, approximately 13% of Copilot API requests failed, and approximately 24% of remote sessions failed to initialize. A partial mitigation at 08:16 UTC reduced the Copilot API error rate to approximately 0.3%, but intermittent failures persisted until a full fix was deployed at 14:15 UTC and recovery was verified by 14:50 UTC. The incident was caused by rate limits being exceeded on a shared infrastructure component. A recently enabled feature increased call volume to this component, and the combined load exceeded capacity limits as traffic increased during business hours. We mitigated the incident by deploying a caching layer to reduce load on shared infrastructure. To prevent recurrence, we are separating rate limit scopes between services, adding monitoring for internal dependency rate limiting, and reducing redundant calls.
Beginning at 02:49 UTC on May 15 2026 and lasting until 03:04 UTC, GitHub.com was unavailable for a subset of customers. This impact has been mitigated and normal service resumed. The issue was rooted in a sudden spike in traffic, with intermittent impact. We've identified the source of the traffic and prevented further disruption.