# Claude Sonnet 5.5 launched with improved performance and reasoning

> Claude Sonnet 5.5 (claude-sonnet-5-5) is now available on the Claude API and all major cloud platforms. The model includes several breaking API changes from Sonnet 5, including changes to thinking blocks, tool use behavior, and computer use toolsets that require migration updates.

Source: https://docs.claude.com/en/release-notes/overview
Published: 2026-09-28
Type: release
Tool: Claude (https://aistack.sh/tool/claude)
Published by: agent
Extraction confidence: 0.95

## Stacks affected

- [Full-stack with Lovable](https://aistack.sh/stack/ai-app-builder-lovable) — $70/mo
- [Cloud IDE with Replit](https://aistack.sh/stack/ai-app-builder-replit) — $40/mo
- [UI-first with v0](https://aistack.sh/stack/ai-app-builder-v0) — $60/mo
- [AI newsletter](https://aistack.sh/stack/ai-newsletter) — $80/mo
- [AI newsletter (Substack)](https://aistack.sh/stack/ai-newsletter-substack) — $53/mo
- [AI thumbnails + ad creative](https://aistack.sh/stack/ai-thumbnails) — $50/mo
- [Android app with AI](https://aistack.sh/stack/android-app-with-ai) — $42/mo
- [Autonomous research agent](https://aistack.sh/stack/autonomous-research-agent) — $59/mo
- [Cheap bulk LLM automation](https://aistack.sh/stack/cheap-bulk-llm) — $140/mo
- [Cold outbound](https://aistack.sh/stack/cold-outbound) — $342/mo
- [Cold outbound (solo)](https://aistack.sh/stack/cold-outbound-lite) — $75/mo
- [iOS + Android with Expo](https://aistack.sh/stack/cross-platform-mobile) — $67/mo
- [Faceless YouTube](https://aistack.sh/stack/faceless-youtube) — $92/mo
- [Faceless YouTube (budget)](https://aistack.sh/stack/faceless-youtube-budget) — $6/mo
- [Inbox triage](https://aistack.sh/stack/inbox-triage) — $51/mo
- [Inbox triage (free)](https://aistack.sh/stack/inbox-triage-free) — $26/mo
- [Indie SaaS](https://aistack.sh/stack/indie-saas) — $75/mo
- [Indie SaaS (Gemini long-context)](https://aistack.sh/stack/indie-saas-gemini) — $75/mo
- [iOS app with AI](https://aistack.sh/stack/ios-app-with-ai) — $48/mo
- [LinkedIn ghostwriting](https://aistack.sh/stack/linkedin-ghostwriting) — $129/mo
- [LinkedIn (for yourself)](https://aistack.sh/stack/linkedin-personal) — $33/mo
- [Live trend research](https://aistack.sh/stack/live-trend-research) — $70/mo
- [Multilingual content factory](https://aistack.sh/stack/multilingual-content) — $60/mo
- [Open-weight LLM stack](https://aistack.sh/stack/open-weight-llm) — $170/mo
- [SEO content engine](https://aistack.sh/stack/seo-content-engine) — $118/mo
- [Antigravity (Google)](https://aistack.sh/stack/ship-code-antigravity) — $40/mo
- [Codex (CLI + cloud)](https://aistack.sh/stack/ship-code-codex) — $40/mo
- [Ship code with AI](https://aistack.sh/stack/ship-code-with-ai) — $50/mo
- [Cross-platform short-form](https://aistack.sh/stack/short-form-cross-platform) — $49/mo
- [Self-hosted scheduler](https://aistack.sh/stack/short-form-self-hosted) — $25/mo
- [TikTok character](https://aistack.sh/stack/tiktok-character) — $92/mo
- [TikTok character (audio + text)](https://aistack.sh/stack/tiktok-character-audio) — $42/mo
- [UGC ad creative](https://aistack.sh/stack/ugc-ads) — $67/mo
- [UGC ads (CapCut-only)](https://aistack.sh/stack/ugc-ads-budget) — $24/mo

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From the aistack.sh changelog: https://aistack.sh/changelog