Klaviyo experienced a major incident on November 18, 2025 affecting Klaviyo API and List Subscription and 1 more component, lasting 5h 7m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- identified Nov 18, 2025, 01:58 PM UTC
Cloudflare declared an incident around 6:30 am US Eastern causing all onsite activities, such as unsubscribe and subscribe preference pages and onsite form submissions to error out. Forms appear, but no requests or related events or subscriptions are processing. API calls are also experiencing 403s. https://www.cloudflarestatus.com/incidents/8gmgl950y3h7 We're currently investigating mitigation steps for the affected features.
- monitoring Nov 18, 2025, 02:34 PM UTC
Fixes have been implemented for some services and we are monitoring the issues.
- resolved Nov 18, 2025, 07:06 PM UTC
This incident has been resolved, as of 2 pm US eastern. All affected components are operational.