API down for EU Data Residency API customers

Write-up

Summary

Between 4:17 PM PDT and 4:24 PM PDT on July 16, 2025, API requests made to eu.api.openai.com experienced a significant error rate. The root cause was a faulty DNS change that left eu.api.openai.com hostname without any DNS records to resolve to. Customer traffic may have been unaffected for cached DNS entries.

Impact

EU Data Residency customers experienced failures for approximately 8 minutes, with residual impact for some customers for up to 13 minutes.
During the outage, customers using Mutual TLS in the API (a beta feature) were also affected.

Mitigation and Prevention
Engineers quickly identified the failed workflow, and the incident was mitigated for most customers within 5 minutes. A small subset of customers experienced lingering failures until 4:30 PM PDT.

Prevention

We are implementing a more robust mechanism for rolling out DNS changes like these to avoid widespread impact.

We apologize for the disruption this caused and are taking steps to strengthen our reliability.

Availability metrics are reported at an aggregate level across all tiers, models and error types. Individual customer availability may vary depending on their subscription tier as well as the specific model and API features in use.