Incident report for November 18, 2025

Resend experienced a service outage on November 18, caused by a Cloudflare outage, affecting their API, Email API, SMTP, and Dashboard services. This incident was due to all API traffic being routed through Cloudflare, which failed to forward requests to Resend's AWS infrastructure, resulting in HTTP 500 errors. The team was alerted to the issue at 11:31 UTC and worked on a workaround using AWS CloudFront to bypass Cloudflare, although the CloudFront solution was not fully deployed. They have since created a runbook to quickly switch to a fallback solution if a similar incident occurs again. Moving forward, Resend is implementing long-term improvements to enhance infrastructure resilience against vendor outages, ensuring critical services remain available, and strengthening incident response processes. The company acknowledges the impact on users and is committed to improving their service reliability.