September 29, 2026
Opus 5.5 Quickly Replaces Opus 5: Became Anthropic's No. 1 on OpenRouter in a Week
As of Sep 28, six days after release, Claude Opus 5.5 became the first Anthropic model on OpenRouter by both spend share and token share. OpenRouter charges $4 per 1 million input tokens and $20 per 1 million output tokens, with a 1 million-token context window.
OpenRouter
@openrouter
Testing Opus 5.5 about a week after launch. Among Anthropic models on OpenRouter, it has taken first place in both spend share and token share. The transition from Opus 5 is moving especially quickly.
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OpenRouter previously used Opus 5. Now simply replace the identifier with `anthropic/claude-opus-5.5` in the API request.
For Claude Code. Connect OpenRouter through `ANTHROPIC_BASE_URL=https://openrouter.ai/api` and a key in `ANTHROPIC_AUTH_TOKEN`; clear `ANTHROPIC_API_KEY`. Anthropic said Opus 5.5 costs 40% less than Opus 5 on typical tasks and responds more than 30% faster.
In the Claude API, the model is available under the identifier `claude-opus-5-5`.
