ChatGPT, Claude, and Grok suffered simultaneous service disruptions on Thursday morning, leaving some users unable to access the AI platforms or generate responses. OpenAI, Anthropic, and xAI each acknowledged problems with their services, though it remains unclear whether the incidents were connected. All affected services were restored by Thursday afternoon.

The simultaneous nature of the disruptions highlighted how dependent on a handful of AI providers many professionals and businesses have become, with no widely adopted fallback when multiple leading chatbots go dark at once.

On X, users said the outages disrupted their work, cutting them off from AI tools they rely on for writing, research, coding, and other daily tasks.

“Claude, Grok and ChatGPT. How can anyone get any work done?” chemist and science communicator Simon Maechling wrote on X.

“ChatGPT is down, and I am immediately 50 IQ points dumber,” joked Dan Shipper, CEO of AI tool developer Every.

OpenAI

OpenAI drew the most complaints, with Downdetector reports peaking at approximately 38,000. Among users who identified a specific problem, 80% selected ChatGPT, 8% Codex, and 7% the app.

The company began investigating elevated errors affecting ChatGPT and Codex at 10:43 a.m. EST, applied a mitigation at 11:17 a.m., and continued monitoring the recovery.

“A routing error starting around 7:43 am PT on Thursday, September 3 made ChatGPT and Codex unavailable for some users across platforms,” an OpenAI spokesperson told Decrypt. “As of about 8:17 a.m. PT on Thursday, a solution was successfully implemented and is continuing to be monitored.”

Anthropic

Anthropic began investigating elevated error rates for Claude Sonnet 5 at 8:37 a.m. EST and marked the problem resolved 19 minutes later, according to its status page. A second incident affecting several Claude models began at 9:26 a.m. EST. Anthropic said it identified the cause, deployed a fix, and ended the incident by 12:16 p.m. EST, without disclosing the cause.

Claude complaints on Downdetector peaked near 1,400. Claude Chat accounted for 35% of categorized reports, followed by Claude Code at 34% and the app at 23%.

"Claude is fully back up after an infrastructure issue caused a partial outage across Claude.ai, Claude Code, Claude Cowork, and the Claude API earlier today. Service was restored at 16:16 UTC,” an Anthropic spokesperson told Decrypt. The broad scope of the incident, spanning the consumer chat interface, developer tools, and the API, underscored how a single infrastructure fault can ripple across an entire product ecosystem.

xAI

Elon Musk’s xAI confirmed an outage affecting Grok’s web and mobile apps, its presence on X, and two U.S. API regions. At 9:30 a.m. EST, the company said it was investigating and working to restore service. Grok complaints on Downdetector peaked at roughly 1,400.

OpenAI, Anthropic, and xAI said the ChatGPT and Codex, Claude, and Grok outages were resolved by 12:55 p.m., 12:16 p.m., and 1:07 p.m. EST, respectively.

History of disruptions and shifting competition

Thursday's outages are the latest in a history of AI chatbot interruptions. ChatGPT has suffered several notable outages, including a December 2024 disruption that knocked the service offline shortly after its Apple Intelligence integration launched, and a June 2025 global outage that lasted more than three hours and affected millions of users. As reliance on these tools has grown, each incident has renewed discussion about reliability and redundancy in workflows built around AI assistants.

The outages also hit as competition among AI assistants continues to shift. At last count, ChatGPT served more than 1 billion weekly active users, Claude had an estimated 300 million monthly active users, and Grok had approximately 117 million monthly active users as of March 2026.

Web-traffic estimates in June 2025 put ChatGPT’s share of the generative AI market near 80%. By August 2025, Gemini and Grok were gaining ground. Data published in May 2026 showed ChatGPT losing more traffic share to its rivals—a more fragmented market in which simultaneous multi-provider outages carry a wider blast radius than in ChatGPT's dominant era.