Replication failures

Incident Report for PubNub

Postmortem

Problem Description, Impact, and Resolution 

At 19:50 UTC on June 10, 2026, we observed a small fraction of publishes originating from US-EAST-1 failing to replicate to subscribers globally. We removed the degraded publisher pod from service and the issue was resolved at 21:21 UTC on June 10, 2026.  The root cause of the incident was triggered by a single process that fell into a degraded state where it continued receiving inbound traffic and passing health checks, but traffic sent outbound from the process was failing at an abnormally high rate. Our automated health check/recovery system did not auto-detect and replace the degraded process because its health check API reported itself as healthy. 

Mitigation Steps and Recommended Future Preventative Measures 

To prevent a similar issue from occurring in the future, we are improving the data within our health check APIs to return more complete performance metrics over a rolling time window. We are enhancing the issue detection logic to detect more patterns that infer process failure, even if the process itself is reporting as healthy.

Posted Jun 16, 2026 - 00:00 UTC

Resolved

Services have returned to normal. A root cause analysis will be published in the coming days. If you believe you were impacted and would like to speak with us, please report impact to support@pubnub.com.
Posted Jun 10, 2026 - 20:45 UTC

Monitoring

The PubNub Technical Staff identified that failures are limited to publishes from US-East and has identified, have applied a fix, and are now monitoring the results.

If you are experiencing issues that you believe to be related to this incident, please report the details to PubNub Support (support@pubnub.com).
Posted Jun 10, 2026 - 20:27 UTC

Investigating

Starting at 17:00 UTC on June 10, a subset of publishes originating from the North America POP failed to replicate to subscribers globally. PubNub Technical Staff is investigating, and more information will be posted as it becomes available.
Posted Jun 10, 2026 - 20:14 UTC
This incident affected: Realtime Network (Publish/Subscribe Service) and Points of Presence (North America Points of Presence).