Claude Sonnet 5.5 is Anthropic’s second model in the Claude 5.5 family, designed as a faster, more cost-efficient upgrade to Sonnet 5. It delivers 30%+ faster output with up to 30% lower cost per task, while supporting coding, AI agents, knowledge work, visual understanding, and everyday AI tasks.

Pricing: Input 160 credits / 1M tokens (≈ $0.80), Output 800 credits / 1M tokens (≈ $4.00). High-tier top-ups include +10% bonus credits. Effective pricing is approximately 10% lower than the above rates.
claude-sonnet-5-5

Automatically append previous messages to maintain multi-turn context. May increase token usage.

Function calling
Thinking process
Max tokens
Stream Response

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Complete guide to using claude-sonnet-5-5

Claude Sonnet 5.5 API – Faster Claude API with Lower Cost on Kie AI

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Generate Outputs 30%+ Faster with Claude Sonnet 5.5 API
Advanced Agentic Coding with Claude Sonnet 5.5 API
Handle Long-Horizon Tasks with Anthropic Claude Sonnet 5.5
Stronger Tool Use for Multi-Step Claude API Workflows
Advanced Knowledge Work with Claude Sonnet 5.5
Improved Image Understanding with Claude Sonnet 5.5 API
BenchmarkSonnet 5.5Sonnet 5Opus 5.5GPT-6 Sol
Terminal-Bench 4.070.6%10.3%66.4%—
FrontierCode 1.1 (Main)46.2% Max / 52.1% Xhigh42.4%54.4%49.3%
CursorBench 4.055.5%34.1%57.8%—
GDPval-AA v2.11844144918461487
AA-Briefcase v1.11811135918221483
Humanity’s Last Exam64.5% with tools54.9% with tools67.7% with tools—
OSWorld 2.180.1% partial57.0% partial81.8% partial—
Chartography61.6% no tools15.6% no tools64.4% no tools53.6% no tools
ComparisonClaude Sonnet 5.5Claude Opus 5.5
Model FocusFast, efficient execution for well-scoped tasksComplex, open-ended work requiring sustained judgment
Agentic Coding70.6% on Terminal-Bench 4.066.4% on Terminal-Bench 4.0
Knowledge Work1844 on GDPval-AA v2.11846 on GDPval-AA v2.1
Long-Horizon WorkHandles extended, multi-step tasks and tool useFocuses on more complex long-running tasks requiring sustained judgment
Visual UnderstandingStrong image, screenshot, and chart understandingStrong visual understanding and computer-use performance
Speed30%+ faster output than Sonnet 5Optimized for complex work rather than speed-first execution
Cost ProfileLower-cost option for well-scoped and repeated workloadsHigher-cost option for more demanding workloads
Best FitCoding, AI agents, analysis, and everyday production tasksComplex analysis, advanced engineering, and open-ended professional work