Outage report · Partial outage

Anthropic API outage on Sep 3, 2026

Elevated errors for multiple models

SeverityPartial outage
StartedSep 3, 2026, 13:26UTC
ResolvedSep 3, 2026, 16:23UTC
Duration2h 57m

What happened

Anthropic API reported a partial outage starting Sep 3, 2026, 13:26 UTC, affecting claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork. It was marked resolved at Sep 3, 2026, 16:23 UTC.

  • The incident lasted 2h 57m from first report to resolution.
  • It was the 3rd longest of 6 significant outages Anthropic API reported in the 12 months up to it.
  • Anthropic API had reported 7 other partial or major outages in the 90 days before it.
  • 12 other vendors we track reported a significant incident within 12 hours of it.

Latest update from Anthropic API

The issue affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 has been resolved. Impact has ended as of 9:16 PT / 16:16 UTC.

Read Anthropic API's official incident report ↗

What our independent monitoring saw

Our independent monitoring of Anthropic API started after this incident, so this report is based on Anthropic API's status page.

Other outages around the same time

Significant incidents other vendors reported within 12 hours of this one.

Anthropic API's overall reliability

36.8/100

Anthropic API has a reliability score of 36.8/100, with 97.53% effective uptime and 36 incidents over the last 90 days.

Visit Anthropic API ↗

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