Starting September 30 at 8am PT, Arena.ai will make Anthropic’s Claude Sonnet 5.5 available for direct testing. Claude Sonnet 5.5 (High) stays in Direct Mode for 48 hours and remains in Battle and Agent Mode afterward.
Arena.ai places Anthropic’s Claude Sonnet 5.5 (High) fourth in Code Arena: WebDev at 1,699 points and a blended $8 per million tokens, 159 points above Sonnet 5 (High).
On Ibragim’s my-mini-bench in pi, Sonnet 5.5 and Opus 5.5 High both passed 30 of 30 runs. Sonnet 5.5 took 46 seconds and $0.10 per task, versus 103 seconds and $0.30 for Opus 5.5 High.
Command Code says Claude Sonnet 5.5 is available across GOAT, Pro, Max, and its API. It says the model runs 30% faster, costs 30% less, and beats Opus 5.5 on Terminal-Bench 4.0.
Databricks says Anthropic’s Claude Sonnet 5.5 is now available across AWS, Azure, and GCP and is governed by Unity Gateway. Databricks says it is more efficient than Sonnet 5 for coding and agentic work and reaches Opus 5-level accuracy on document understanding, parsing, and search.
ClaudeDevs says Claude Sonnet 5.5 is out and has published a guide for building with it, covering model choice against Opus 5.5, migration from Sonnet 5, and use in Claude Code.
Cline says Sonnet 5.5 beats Opus 5.5 on Terminal-Bench 4.0 while costing half as much. Cline also says it uses fewer tokens than earlier models, cuts cost by up to 30% per task, and generates output 30% faster than its predecessor.
OpenRouter prices Claude Sonnet 5.5 at $2 per million input tokens and $10 per million output tokens, with a 1 million-token context window. Those rates are unchanged from Sonnet 5.
OpenRouter now offers Anthropic’s Claude Sonnet 5.5. OpenRouter says it is significantly smarter than Sonnet 5, writes more clearly, and is 30% faster and about 30% cheaper for most work.
Pi tells users to run pi update --models alongside Claude’s introduction of Claude Sonnet 5.5. Claude says the model is the second in the Claude 5.5 family, runs more than 30% faster than Sonnet 5, and costs up to 30% less for most work.
Artificial Analysis says Claude Sonnet 5.5 scores 56 on its Intelligence Index at max effort, two points behind Claude Opus 5.5 (max), while using the highest output-token count it has measured and costing about $7.60 per task.
Arena.ai has added Claude Sonnet 5.5 by AnthropicAI to Agent Arena and to Battle Mode for WebDev, Text, Vision, and Document. Claude says it is the second Claude 5.5 model, runs more than 30% faster than Sonnet 5, and costs up to 30% less for most work.
Claude says Claude Sonnet 5.5 is available everywhere today. Claude Haiku 5.5 is expected to join the Claude 5.5 family in the coming weeks.