- API keys are self-serve: sign up at https://openrouter.ai and create a key at https://openrouter.ai/settings/keys. No sales contact is needed.
- Free tier: models with the `:free` variant cost nothing, and the free models router at `openrouter/free` picks one for you. Free usage is rate limited per day; buying credits raises the limit. See https://openrouter.ai/docs/api-reference/limits.md.
- Pricing is pay-as-you-go per token with no markup on the provider's price: https://openrouter.ai/pricing.
- MCP server for agents: https://mcp.openrouter.ai/mcp (OAuth in the browser, hosted by OpenRouter). Setup guide: https://openrouter.ai/docs/guides/overview/mcp-server.md.
- OpenAPI description of the whole API: https://openrouter.ai/openapi.json.
