Claude Sonnet 5.5
Claude Sonnet 5.5Alternatives?
CheaperGPT-6 Astraxhigh+25%-58%$2.31Monitoring can return HTTP 403+2BetterGPT-6.1 Solmedium+16%-96%$0.21Remove unsupported parameters+5
OpenKimi K3max-15%-63%$2.00Sampling parameters are fixed+3Lower effortSame modelhighsame-84%$0.88
CheaperMuse Wondermax+19%-17%$4.52Only auto tool_choice is supported+5GPT-6 Astraxhigh+25%-58%$2.31Monitoring can return HTTP 403+2GPT-6.1 Solhigh+24%-94%$0.32Remove unsupported parameters+5Muse Wondermax+19%-17%$4.52Only auto tool_choice is supported+5Claude Opus 5.5high+12%-67%$1.82No forced tool use+5Claude Fable 5.1low+9%-57%$2.37Replace forced tool_choice+5GPT-6.1 Solmedium+16%-96%$0.21Remove unsupported parameters+5GPT-5.6 Solhigh+8%-85%$0.81GPT-6 Astralow+18%-85%$0.82Monitoring can return HTTP 403+2Claude Opus 5.5high+12%-67%$1.82No forced tool use+5Claude Fable 5.1low+9%-57%$2.37Replace forced tool_choice+5Kimi K3maxOpen-15%-63%$2.00Sampling parameters are fixed+3
MiMo v2.6 ProthinkingOpen-26%-98%$0.13No PDF input+4Muse Spark OpenxhighOpen-28%-85%$0.84Reasoning off leaves output unchanged · Self-hosted / llama.cpp+1
DeepSeek V4.1 Flash 1017maxOpen-33%-95%$0.26No PDF input+5
Qwen3.8 27BxhighOpen-36%-82%$1.01Context: 1M → 262K+5Claude Opus 5.5maxsame+10%$5.98No forced tool use+5Claude Fable 5.1maxsame+40%$7.63Replace forced tool_choice+5Claude Fable 5max-7%+60%$8.75Claude Opus 4.8max-12%-25%$4.08Claude Opus 5max-16%+7%$5.86Claude Haiku 5.5max-19%-96%$0.21Remove sampling parameters+5Claude Sonnet 4.6max-39%-54%$2.49Claude Sonnet 5max-49%-7%$5.09All Anthropic models →History
7 versionsBenchmarks
in Chat & KnowledgeWatch out 6
No forced tool use›
Forced tool_choice any or tool returns HTTP 400; remove the forced choice. Source ↗
Replace disabled thinking›
Disabled thinking returns HTTP 400; use between_tools for the lowest thinking setting. Source ↗
No manual thinking budgets›
Manual thinking budgets and extra between_tools fields return HTTP 400; remove manual budgets and send between_tools without display, budget_tokens or block_binding. Source ↗
Remove sampling parameters›
Non-default temperature, top_p or top_k returns HTTP 400; remove these parameters. Source ↗
No assistant prefill›
A prefilled final assistant turn returns HTTP 400; remove that prefill. Source ↗
Old computer tool rejected · Claude API / Google Cloud›
The computer_20251124 tool returns HTTP 400 on the Claude API and Google Cloud; use computer_toolset_20260801 there. Source ↗
FAQ
How much does Claude Sonnet 5.5 cost?›
$2 per 1M input tokens and $10 per 1M output tokens; cached input $0.10 per 1M. A typical benchmark task costs about $5.46 at max effort.
Is Claude Sonnet 5.5 free to use?›
There is no free API; the cheapest paid price is $2 per 1M input tokens.
How good is Claude Sonnet 5.5, and what is it best at?›
#5 of 334 in Chat & Knowledge, #1 of 132 in Coding, #3 of 133 in Agents & Tool Use, #15 of 195 in Writing & Language, #9 of 133 in Vision & Documents. Strongest at: Coding, Agents & work tasks, Reasoning, Long context, Knowledge.
Is Claude Sonnet 5.5 better than Claude Sonnet 4.5?›
On GDP.pdf · AA all-pass, Claude Sonnet 5.5 scores 25.8 vs 5.2 — higher. It is 881% more expensive per task.
How can I use Claude Sonnet 5.5?›
Through the API of Amazon Bedrock, Anthropic, Azure, Claude Platform on AWS, DeepInfra and 1 more.
What is the context window of Claude Sonnet 5.5?›
1M tokens, with up to 128K output tokens.
When was Claude Sonnet 5.5 released? Is there a newer version?›
Released 2026-09-28. It is the current version in its line.
Is Claude Sonnet 5.5 open source?›
No, Claude Sonnet 5.5 is a closed model available through an API. The closest open-weights option here is Kimi K3.
Can Claude Sonnet 5.5 read images?›
It accepts text and images, PDF files as input.
What is Claude Sonnet 5.5?›
Claude Sonnet 5.5 is a closed language model from Anthropic, released Sep 2026, the successor to Claude Sonnet 4.5.
What are the best alternatives to Claude Sonnet 5.5?›
GPT-6 Astra (cheaper), GPT-6.1 Sol (better), Kimi K3 (open weights).