Critical incident

Crossref: Main website down between 05:46 UTC and 06:47 UTC

Affected: Crossref website

Current status of Crossref: Operational — live Crossref status

Timeline

1. Apr 17, 2026, 06:32 UTC
   investigating
   The main Crossref website (www.crossref.org) has been down since 05:46 UTC. We are investigating the cause of the issue.
2. Apr 17, 2026, 07:04 UTC
   monitoring
   The website is available again. We are monitoring the situation.
3. Apr 17, 2026, 10:23 UTC
   resolved
   From 05:46 UTC on 17 April we experienced a sustained surge of traffic to our website, which was caused by bot activity distributed across multiple IP addresses. The service recovered automatically without intervention after about an hour, and we have since applied tighter rate-limiting to the source. We are also reviewing options to further improve the scalability and resilience of the service going forward.

Updates as published by Crossref (original).