# Klaviyo: Data processing delays

- Impact (vendor’s label): minor
- Status: resolved
- Started: 2025-12-18 04:10 UTC · Resolved: 2025-12-18 06:36 UTC · Duration: 2.4 h
- Updates: 4 · Affected components: Email Sending, Email Sending - Flow Email Sending, Segmentation, Segments, Klaviyo App, Klaviyo App - Klaviyo App, Flow Triggering, Processing, Klaviyo API, Server-side, Email Sending, Email Sending - Campaign Email Sending
- [Vendor status page: https://stspg.io/pjsg6jl9cwgq](https://stspg.io/pjsg6jl9cwgq)
- [Company: Klaviyo](https://rewindex.com/company/klaviyo.md)

## Timeline of updates

- **investigating** 2025-12-18 04:10 UTC: 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.
- **identified** 2025-12-18 05:12 UTC: The issue has been identified and a fix is being implemented.
- **monitoring** 2025-12-18 06:06 UTC: A fix has been implemented and we are monitoring the results.
- **resolved** 2025-12-18 06:36 UTC: This incident has been resolved.


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Canonical: https://rewindex.com/company/klaviyo/incidents/g1c5f6xjg4mj · Markdown: https://rewindex.com/company/klaviyo/incidents/g1c5f6xjg4mj.md · JSON: https://rewindex.com/api/v1/companies/klaviyo/incidents/g1c5f6xjg4mj · Generated 2026-10-18T09:59:52.561Z