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Anthropic releases Claude Sonnet 5.5

Event: · Published:

Anthropic announced Claude Sonnet 5.5 on September 28, 2026, describing it as a faster, lower-cost complement to Claude Opus 5.5. Anthropic says it is available in the Claude apps and on its platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure. Anthropic's model documentation lists the API identifier claude-sonnet-5-5 with a 1M-token context window. It is a hosted model; Anthropic has not published its weights.12

Related catalog entries

Sources

  1. 1.
    Claude Sonnet 5.5 (external site: anthropic.com)

    Anthropic · Official page · published Sep 28, 2026 · accessed Oct 1, 2026

  2. 2.
    Models overview (Claude API documentation) (external site: platform.claude.com)

    Anthropic · Documentation · accessed Oct 1, 2026

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