Anthropic's Claude Outage Disrupts 12,000+ Users (Sept 29)

Anthropic’s Claude AI experienced a significant service disruption on September 29, 2026, affecting thousands of users across multiple platforms including Claude Chat, Claude Code, and Claude Cowork. The outage impacted more than 12,000 users as of 7:34 a.m. PT, with a confirmed partial outage affecting Claude, Claude Code, Claude Cowork, as well as the Claude API and Console. While most services were restored within approximately one hour, the incident marks the latest in a series of reliability issues for the popular AI assistant.

Timeline of the Outage

The errors began at 14:00 UTC and were mitigated at 14:36 UTC, with Anthropic responding quickly to address the widespread disruptions. The company confirmed it was aware of the outage just prior to 10:30am ET (7:30am PT), after user reports began flooding monitoring services like DownDetector.

The majority of users (47%) reported issues with Claude Chat, while 39% experienced problems with the mobile app, and a further 7% with Claude Code. Anthropic noted it had applied a mitigation and error rates dropped substantially, though some sign-in attempts, account actions and Claude Code and Cowork sessions were still failing.

All services returned to normal operations at 14:59 UTC, bringing the total outage duration to approximately one hour for most functionality.

Services Affected by the Disruption

The outage extended beyond the consumer-facing Claude Chat interface to impact developer tools and enterprise features. The platform’s status checker reported investigating reports of degraded performance affecting claude.ai, platform.claude.com, the Claude API, Claude Code, and Claude Cowork.

A secondary issue prevented many users from signing in (single sign-on and Sign in with Apple were unavailable), starting new chats, voice conversations and Claude Code or Cowork sessions, making purchases, and uploading files. During the peak of the incident, Anthropic warned users not to sign out of their accounts until the login issues were resolved.

The disruption affected both individual users and development teams relying on Claude’s API for production applications. Some requests to the Claude API returned errors during the outage window, potentially impacting businesses integrated with Anthropic’s services.

Recent Pattern of Service Interruptions

This September 29 incident continues a pattern of reliability challenges for Claude throughout the month. There were partial Claude outages on September 22, September 15, and September 11, as well as a major outage on September 3 that happened at the same time as outages with other AI models including ChatGPT and Grok.

The status page’s incident history lists 13 incidents for September 2026, including the September 29 event, suggesting persistent infrastructure or scaling challenges as the platform continues to grow its user base.

Anthropic’s Response and Recovery Efforts

Anthropic demonstrated relatively quick response times throughout the incident. The incident was initially listed as “Investigating” at 14:21 UTC, and seven minutes later, at 14:28 UTC, Anthropic updated the status page to confirm that the Claude API was also affected.

Existing conversations were mostly working again after the mitigation was applied at 10:36 AM ET, with the company providing regular updates through its official status page. The transparency and communication during the outage allowed users to track recovery progress in real time.

Impact on Claude Code and Developer Tools

Claude Code, Anthropic’s code-focused tool designed for developers, was among the services significantly affected by the outage. The disruption came at a time when the platform has been expanding its enterprise and developer-facing capabilities, making reliability particularly critical for professional users.

Beyond the immediate outage, Claude Code has been subject to other recent changes that may affect developer workflows. Compatibility issues between different versions of Claude Sonnet models have been reported, with code written for earlier versions potentially breaking when used with newer model releases.

Key Facts

Outage Duration: Approximately one hour, from 14:00 UTC to 14:59 UTC on September 29, 2026
Peak Impact: Over 12,000 users reported problems, with nearly 4,000 reports spiking at 2:19 PM UTC on DownDetector
Services Affected: Claude Chat, Claude Code, Claude Cowork, Claude API, Console, mobile apps, and authentication systems
Primary Issues: 47% of reports involved Claude Chat problems, 39% mobile app issues, and 7% Claude Code disruptions
September Incident Count: 13 total incidents recorded for September 2026
Mitigation Time: Initial errors mitigated within 36 minutes (14:00 to 14:36 UTC)

Looking Forward

As Anthropic continues to position Claude as a leading AI assistant for both consumer and enterprise applications, service reliability remains a critical factor for user confidence and business adoption. The frequency of September outages, particularly affecting developer-focused tools like Claude Code, may prompt increased scrutiny from organizations evaluating AI platforms for mission-critical applications.

While the company’s rapid response and transparent communication during outages are positive signs, the underlying infrastructure challenges that have led to 13 incidents in a single month will need to be addressed to maintain competitive positioning against rivals like OpenAI’s ChatGPT and Google’s Gemini.