# Claude Sonnet 5.5

> Anthropic's fast, capable middle model. It scores close to the flagships and writes faster than Opus.

- Maker: Anthropic (https://docs.anthropic.com/en/docs/about-claude/models)
- Type: Reasoning
- Artificial Analysis Intelligence Index: 54 (max setting)
- Context window: 1M
- Output speed: 137 tokens a second
- Scores checked 30 October 2026 at https://artificialanalysis.ai/leaderboards/models

## Where to use it through an API

- Anthropic: model id `claude-sonnet-5-5`, fast and capable
- Vercel AI Gateway: model id `anthropic/claude-sonnet-5.5` (free key available)

## Use it free

- Vercel AI Gateway free API key: how to get one: https://www.multiscreenai.com/free/vercel-ai-gateway-api-key

## Use it with every other AI at once

MultiScreenAI (https://www.multiscreenai.com) puts Claude Sonnet 5.5 on one screen next to ChatGPT, Claude, Gemini and 300+ models: one message goes to every panel, and a timed, blind test mode shows which answers best. Free during the beta with your own API keys.
AI agents and coding harnesses (Claude Code, Codex, Cursor, Gemini CLI) can ask Claude Sonnet 5.5 and other models at once through the MCP server at https://www.multiscreenai.com/api/mcp/ai; setup: https://www.multiscreenai.com/mcp