Service update · Anthropic
Claude's Messages API adds message threads in public beta
- Effective time
- Review updated
The API keeps the conversation on the server, so later requests send only the new messages, making requests smaller and the first token arrive sooner. It needs the message-threads-2026-08-12 beta header. A thread expires 5 minutes after its last request and is deleted within an hour. It works on the Claude API, Claude Platform on AWS, Google Cloud (Anthropic managed) and Microsoft Foundry. Anthropic says it's billed at standard token rates.