OpenRouter is an API gateway for AI models, made by OpenRouter, Inc. It is one interface through which a program reaches more than 500 models, for example from Google, OpenAI and Anthropic, served by more than 80 providers. The models produce text, images, video and audio.
A developer creates an account, buys credits and creates an API key. The program then sends each request to OpenRouter's single API, which is compatible with the OpenAI API format, and names the model it wants; OpenRouter forwards the request to a provider that serves that model and returns the answer. When one provider goes down, the request falls back to another provider. Data policies make sure that prompts go only to the models and providers an organization trusts. The same account gives activity logs, budgets and spending controls, and a chat page for trying models by hand.
OpenRouter has no subscription. Each request costs the provider's list price, deducted from prepaid credits; OpenRouter charges its fee when the credits are bought. A free plan allows limited use of more than 25 free models.