Klaviyo experienced a minor incident on December 18, 2025, lasting —. The incident has been resolved; the full update timeline is below.
Update timeline
- monitoring Dec 18, 2025, 06:36 AM UTC
Dec 18, 01:36 EST Resolved - This incident has been resolved. Dec 18, 01:06 EST Monitoring - A fix has been implemented and we are monitoring the results. Dec 18, 00:12 EST Identified - The issue has been identified and a fix is being implemented. Dec 17, 23:10 EST Investigating - Starting around 9:52pm US Eastern, a database upgrade failure caused data processing delays in-app. As a result, we are experiencing delays in event processing, flows, unsubscribes, segmentation, sending for certain campaigns, and v3 APIs. No data loss is expected. We are actively working to resolve the incident and will provide updates when possible.