Outage report · Major outage
Trello outage on Dec 12, 2025
500 Errors being experienced by Trello users
What happened
Trello reported a major outage starting Dec 12, 2025, 06:40 UTC, affecting Trello.com, API, Atlassian Support - Support Portal, Atlassian Support Ticketing, Atlassian Support Knowledge Base. It was marked resolved at Dec 12, 2025, 07:41 UTC.
- The incident lasted 1h 2m from first report to resolution.
- Trello had reported 1 other partial or major outage in the 90 days before it.
- 4 other vendors we track reported a significant incident within 12 hours of it.
Latest update from Trello
### Summary On December 12, 2025, between 05:31 UTC and 07:11 UTC, Trello customers experienced errors or slow loading times due to a dependency library upgrade that caused high resource usage. The incident was detected within 1 minute by the automated monitoring system and mitigated by rolling back the version of the dependency library which put Atlassian systems into a known good state. The total time to resolution was 1 hour and 41 minutes. ### **IMPACT** The issue caused service disruption for all Trello customers on December 12, 2025 between 05:31 UTC and 07:11 UTC. Users experienced degraded service between 05:31 UTC and 06:32 UTC, and most users were unable to load Trello between 06:32 UTC to 07:07 UTC. ### **ROOT CAUSE** The issue was caused by an upgrade to a dependency library. As a result, there was an increase in system memory consumption causing startups to take longer than expected. When the startup time exceeded the allowed threshold, the worker process was flagged
What our independent monitoring saw
Our independent monitoring of Trello started after this incident, so this report is based on Trello's status page.
Other outages around the same time
Significant incidents other vendors reported within 12 hours of this one.
Trello's overall reliability
Trello has a reliability score of 100.0/100, with 100% effective uptime and 0 incidents over the last 90 days.
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