At approximately 13:20 UTC on June 9, 2026, we observed elevated publish errors and message replication failures in our publish/subscribe service, which also caused latency in other PubNub services globally. Customers may have experienced increased publish error rates, delayed or missed message delivery, delayed message persistence, and increased latency for Functions and Events & Actions workflows.
The root cause of the incident was an unusually large concentration of global publish traffic that was not limited by our throttling layers. That traffic created resource pressure in the publish and replication layers, increased load on storage systems, and caused downstream processing delays in dependent services. We mitigated the issue by adjusting targeted traffic controls, increasing capacity for affected publish and replication components, and isolating the high-volume traffic pattern to reduce broader platform impact. The issue was resolved at approximately 13:48 UTC on June 9, 2026.
This issue occurred because we did not have sufficient automated controls and isolation processes in place to protect shared infrastructure from this type of exceptional traffic pattern. As a result, the increased load affected multiple services before mitigation could be fully applied.
To prevent a similar issue from occurring in the future, we have isolated the identified high-volume traffic pattern onto dedicated infrastructure and also increased baseline capacity for the affected components across our PoPs.
We are also further strengthening our traffic detection and management processes for exceptional load patterns so they can be identified and contained earlier without cascading impact across dependent services.