# Claude Sonnet 5\.5, the second model in the Claude 5\.5 family

[Reference page](https://posts.design/claude-sonnet-5-5-the-second-model-in-2026-09-28) · [Markdown](https://posts.design/claude-sonnet-5-5-the-second-model-in-2026-09-28.md) · [Original source](https://x.com/claudeai/status/2104633115620823187)

Introducing Claude Sonnet 5\.5, the second model in the Claude 5\.5 family\.

It’s a clear upgrade over Sonnet 5, runs more than 30% faster, and costs up to 30% less for most work\.

- Kind: post
- Media: video
- Posting account: Claude · @claudeai
- Account: [claudeai](https://x.com/claudeai)
- Represented brand: Claude
- Categories: Launch
- Subjects: AI
- Source published: 2026\-09\-28T18:03:31\.000Z
- Captured: 2026\-09\-28
- Added to posts.design: 2026\-09\-29T00:46:29\.794Z
- Recorded views: 12733995 · captured 2026\-10\-12T14:57:54\.841Z · refresh\-observed\-public

![Claude Sonnet 5\.5, the second model in the Claude 5\.5 family — public x\-twitter post media curated for social post design inspiration\.](https://posts.design/images/posts/x-twitter-claudeai-2104633115620823187-claude-sonnet-5-5-second-model.webp)

1280 × 720

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