GitHub is having issues now

Source: Hacker News

Incident Summary

• Date: April 20 – 21, 2026
• Affected services: Code scanning default setup, Code Quality, Project boards
• Impact:
  • Code scanning and Code Quality analyses were not triggered on newly opened pull requests.
  • Newly created issues did not appear on project boards.
• Cause: A serialization error prevented proper triggering of code scanning, code quality analyses, and project‑board updates.
• Mitigation: Deployed a fix that restored event publishing for code scanning and code quality, updated project‑board event consumers, and performed a re‑index of affected project items.
• Prevention: Strengthening schema validations and improving monitoring for drops in publishing on critical topics.

Timeline

• Apr 20 13:28 UTC – Investigating reports of impacted performance for some GitHub services.
• Apr 20 13:57 UTC – Investigation ongoing.
• Apr 20 14:38 UTC – Actively working to mitigate an issue affecting code scanning default setup and code quality on pull requests. Users may experience analyses not being triggered.
• Apr 20 15:20 UTC – Deploying mitigations to unblock code scanning default setup and code quality features on pull requests.
• Apr 20 16:16 UTC – Continuing work on mitigation to unblock code scanning and code quality.
• Apr 20 16:48 UTC – Code scanning default setup and Code Quality triggers are back up. PRs not processed will require a new push to trigger analyses. Working on new issues not showing on project boards.
• Apr 20 17:32 UTC – Continued mitigation for new issues not showing on project boards.
• Apr 20 18:08 UTC – Ongoing mitigation for new issues not showing on project boards.
• Apr 20 18:20 UTC – Deployment underway to fix new issues not appearing in projects.
• Apr 20 18:20 UTC – Issue mitigated. Newly created issues linked to projects should now function; remaining linked issues may take ~5 hours to re‑index.
• Apr 20 18:21 UTC – Monitoring the mitigation.
• Apr 20 21:36 UTC – Degradation mitigated; monitoring continues.
• Apr 21 03:10 UTC – Degradation mitigated; monitoring continues.
• Apr 21 04:18 UTC – Issue remains mitigated; linked issues may need ~3 hours to render correctly.
• Apr 21 05:04 UTC – Degradation mitigated; monitoring continues.

Resolution

• The serialization error was fixed by deploying a code change that restored event publishing for code scanning and code quality, updating project‑board event consumers, and re‑indexing affected project items.
• Ongoing efforts include strengthening schema validations and improving monitoring for drops in publishing on critical topics to prevent recurrence.