GitHub Outage History

On April 1st, 2026 between 14:40 and 17:00 UTC the GitHub code search service had an outage which resulted in users being unable to perform searches. The issue was initially caused by an upgrade to the code search Kafka cluster ZooKeeper instances which caused a loss of quorum. This resulted in application-level data inconsistencies which required the index to be reset to a point in time before the loss of quorum occurred. Meanwhile, an accidental deploy resulted in query services losing their shard-to-host mappings, which are typically propagated by Kafka. We remediated the problem by performing rolling restarts in the Kafka cluster, allowing quorum to be reestablished. From there we were able to reset our index to a point in time before the inconsistencies occurred. The team is working on ways to improve our time to respond and mitigate issues relating to Kafka in the future.

On March 31, 2026, between 06:15 UTC and 15:30 UTC, the GitHub billing usage reports feature was degraded due to reduced server capacity. Customers requesting billing usage reports and loading the top usage by organization and repository on the billing overview and usage pages were impacted. The average error rate for usage report requests was 15%, peaking at 98% over an eight-minute window. For the billing pages, an average of 56% of requests failed to load the top usage cards. The root cause was an increase in billing usage report requests with large datasets, which exhausted the capacity of the nodes responsible for reporting data. There was no impact on billing charges. We mitigated the incident by adjusting our auto-scaling thresholds to better meet our capacity needs. We are working to improve our metrics to reduce time to detection and mitigation for similar issues in the future.

On March 30, 2026, between 10:11 UTC and 13:25 UTC, GitHub Actions experienced degraded performance. During this time, approximately 2.65% of workflow jobs triggered by pull request events experienced start delays exceeding 5 minutes. The issue was caused by replication lag on an internal database cluster used by Actions, which triggered write throttling in our database protection layer and slowed job queue processing. The replication lag originated from planned maintenance to scale the internal database. Newly added database hosts triggered guardrails in the throttling layer, restricting write throughput. The incident was mitigated by excluding the new hosts from replication delay calculations. To prevent recurrence, we have updated our maintenance procedures to ensure new hosts are excluded from throttling assessments during scaling operations. Additionally, we are investing in automation to streamline this type of maintenance activity.

On March 24, 2026, between 15:57 UTC and 19:51 UTC, the Microsoft Teams Integration and Teams Copilot Integration services were degraded and unable to deliver GitHub event notifications to Microsoft Teams. On average, the error rate was 37.4% and peaked at 90.1% of requests to the service -- approximately 19% of all integration installs failed to receive GitHub-to-Teams notifications in this time period. This was due to an outage at one of our upstream dependencies, which caused HTTP 500 errors and connection resets for our Teams integration. We coordinated with the relevant service teams, and the issue was resolved at 19:51 UTC when the upstream incident was mitigated. We are working to update observability and runbooks to reduce time to mitigation for issues like this in the future.

On March 18, 2026, between 18:18 UTC and 19:46 UTC all webhook deliveries experienced elevated latency. During this time, average delivery latency increased from a baseline of approximately 5 seconds to a peak of approximately 160 seconds. This was due to resource constraints in the webhook delivery pipeline, which caused queue backlog growth and increased delivery latency. We mitigated the incident by shifting traffic and adding capacity, after which webhook delivery latency returned to normal. We are working to improve capacity management and detection in the webhook delivery pipeline to help prevent similar issues in the future.

On 16 March 2026, between 14:16 UTC and 15:18 UTC, Codespaces users encountered a download failure error message when starting newly created or resumed codespaces. At peak, 96% of the created or resumed codespaces were impacted. Active codespaces with a running VSCode environment were not affected. The error was a result of an API deployment issue with our VS Code remote experience dependency and was resolved by rolling back that deployment. We are working with our partners to reduce our incident engagement time, improve early detection before they impact our customers, and ensure safe rollout of similar changes in the future.

On March 11, 2026, between 14:25 UTC and 14:34 UTC, the REST API platform was degraded, resulting in increased error rates and request timeouts. REST API 5xx error rates peaked at ~5% during the incident window with two distinct spikes: the first impacting REST services broadly, and the second driven by sustained timeouts on a subset of endpoints. The incident was caused by a performance degradation in our data layer, which resulted in increased query latency across dependent services. Most services recovered quickly after the initial spike, but resource contention caused sustained 5xx errors due to how certain endpoints responded to the degraded state. A fix addressing the behavior that prolonged impact has already been shipped. We are continuing to work to resolve the primary contributing factor of the degradation and to implement safeguards against issues causing cascading impact in the future.

On March 11, 2026, between 13:00 UTC and 15:23 UTC the Copilot Code Review service was degraded and experienced longer than average review times. On average, Copilot Code Review requests took 4 minutes and peaked at just under 8 minutes. This was due to hitting worker capacity limits and CPU throttling. We mitigated the incident by increasing partitions, and we are improving our resource monitoring to identify potential issues sooner.

On March 5th, 2026, between approximately 00:26 and 00:44 UTC, the Copilot service experienced a degradation of the GPT 3.5 Codex model due to an issue with our upstream provider. Users encountered elevated error rates when using GPT 3.5 Codex, impacting approximately 30% of requests. No other models were impacted. The issue was resolved by a mitigation put in place by our provider.

On March 3, 2026, between 19:44 UTC and 21:05 UTC, some GitHub Copilot users reported that the Claude Opus 4.6 Fast model was no longer available in their IDE model selection. After investigation, we confirmed that this was caused by enterprise administrators adjusting their organization's model policies, which correctly removed the model for users in those organizations. No users outside the affected organizations lost access. We confirmed that the Copilot settings were functioning as designed, and all expected users retained access to the model. The incident was resolved once we verified that the change was intentional and no platform regression had occurred.

On March 2nd, 2026, between 7:10 UTC and 22:04 UTC the pull requests service was degraded. Users navigating between tabs on the pull requests dashboard were met with 404 errors or blank pages. This was due to a configuration change deployed on February 27th at 11:03 PM UTC. We mitigated the incident by reverting the change. We’re working to improve monitoring for the page to automatically detect and alert us to routing failures.