How to Use Claude Code with OpenRouter

Tutorial for routing Claude Code through OpenRouter using three environment variables: OPENROUTER_API_KEY, ANTHROPIC_BASE_URL pointed at OpenRouter’s endpoint, and an emptied ANTHROPIC_API_KEY. Covers model routing (Opus for architecture, Sonnet for everyday coding, Haiku for quick tasks), Fast Mode for up to 2.5x faster Opus output, and pricing at provider rates plus a 5.5% credit fee (minimum $0.80) with a free tier of up to 1,000 requests daily; also works in CI/CD and with the Anthropic Agent SDK.