release

Claude Sonnet 5.5 launched with improved performance and reasoning

docs.claude.comagent

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.

Stacks this affects

Claude ships in 34 tested stacks here.

Full-stack with Lovable
Code · Builder
$70/mo
Cloud IDE with Replit
Code · Builder
$40/mo
UI-first with v0
Code · Builder
$60/mo
AI newsletter
Writing · Newsletter
$80/mo
AI newsletter (Substack)
Writing · Newsletter
$53/mo
AI thumbnails + ad creative
Marketing · Visual
$50/mo
Android app with AI
Code · Mobile
$42/mo
Autonomous research agent
Research · Intelligence
$59/mo
Cheap bulk LLM automation
Code · Backend
$140/mo
Cold outbound
Sales · Outbound
$342/mo
Cold outbound (solo)
Sales · Outbound
$75/mo
iOS + Android with Expo
Code · Mobile
$67/mo
Faceless YouTube
Video · Creator
$92/mo
Faceless YouTube (budget)
Video · Creator
$6/mo
Inbox triage
Productivity · Inbox
$51/mo
Inbox triage (free)
Productivity · Inbox
$26/mo
Indie SaaS
Code · Builder
$75/mo
Indie SaaS (Gemini long-context)
Code · Builder
$75/mo
iOS app with AI
Code · Mobile
$48/mo
LinkedIn ghostwriting
Writing · Agency
$129/mo
LinkedIn (for yourself)
Writing · Personal
$33/mo
Live trend research
Research · Intelligence
$70/mo
Multilingual content factory
Writing · Content
$60/mo
Open-weight LLM stack
Code · Backend
$170/mo
SEO content engine
Writing · SEO
$118/mo
Antigravity (Google)
Code · Workflow
$40/mo
Codex (CLI + cloud)
Code · Workflow
$40/mo
Ship code with AI
Code · Workflow
$50/mo
Cross-platform short-form
Marketing · Distribution
$49/mo
Self-hosted scheduler
Marketing · Distribution
$25/mo
TikTok character
Video · Creator
$92/mo
TikTok character (audio + text)
Video · Creator
$42/mo
UGC ad creative
Marketing · Ads
$67/mo
UGC ads (CapCut-only)
Marketing · Ads
$24/mo
All Claude changes and pricing

More Claude

releaseClaude Haiku 5.5 launched with 1M context and adaptive thinkingfeatureClaude Sonnet 5.5 prompt cache reads reduced to $0.10 per million tokensfeatureModels API adds line field to group models by family without parsing IDsfeatureModels API now returns line field for grouping models by familyshutdownClaude Sonnet 4.5 deprecation scheduled for November 30, 2026 retirementshutdownClaude Sonnet 4.5 deprecated with November 30, 2026 retirement date