Better prices , better uptime , no subscriptions. Featured Models 500+ active models on 80+ providers Featured Agents 250k+ apps using OpenRouter with 4.2M+ users globally The easiest way to go from idea to app An autonomous agent that grows with you The open-source AI coding agent Create an account to get started. You can set up an org for your team later. Credits can be used with any model or provider.

Get your API key Create an API key and start making requests. Fully OpenAI compatible . Recent Blog Posts How to Test Tool-Calling Accuracy in AI Agents An agent can call the wrong tool, or call the right tool with the wrong arguments. This guide covers three ways to test each failure mode, a Python harness that grades both, and how to run the same test cases against several tool-capable models through OpenRouter. Building a Golden Eval Dataset from Production Traffic A golden eval dataset is a curated set of production inputs with reviewed expected outputs, versioned in Git and run before every deploy. This guide covers the five steps to build one from live traffic and how to run the same set against many candidate models through one API. AI Agent Regression Testing After a Prompt or Model Change An agent's behavior can change when you edit a prompt, swap a model, change a tool schema, or change what retrieval returns. This guide covers the locked case set, the per-case behavioral contract, and how to run the same suite against two concrete model slugs through OpenRouter so the diff shows what the change did.