Developers

Fuse is a proxy in front of the provider APIs you already pay for. Your app sends a Fuse key. Fuse checks the project ceiling, then calls the provider that owns the model, with the key stored on that project.

The base URL is https://fuse.ospalabs.com/v1. The credential your app holds is named FUSE_API_KEY. It is not an OpenAI key, an Anthropic key, or a Google key.

Start with the quickstart, then authentication and chat completions. Each topic in the sidebar is its own page.

Fuse does not choose a provider from a setting on the key. The model field does. The key you put in FUSE_API_KEY only identifies the project. OpenAI, Anthropic, Google, Mistral, xAI, and custom gateways are selected after that, from the model id and the keys stored on the project.