API Routing

API Routing is a middleware approach that automatically finds the right path to the appropriate model among multiple AI models for a given request. Like a switchboard operator connecting an incoming call to the right department, it lets a developer send a request to a single endpoint, which then routes it behind the scenes to whatever is needed — whether that's an OpenAI model or Google Gemini.

With this kind of service, developers don't need to sign separate contracts with each model provider or learn each one's connection method — they only need to deal with a single endpoint. This middleware layer also handles things like routing requests to a cheaper model based on the nature of the request, or automatically switching to another model if a particular one isn't responding.

Recently, payments company Stripe acquired OpenRouter, an API routing service, for a large sum, drawing attention to how money is flowing not so much into the models themselves but into this layer that connects and distributes them.

In articles, it's mentioned as "the case of payments company Stripe acquiring API routing service OpenRouter for $7 billion." It's easy to mistakenly assume OpenRouter builds AI models itself, but the key point is that it's actually a middleware service that connects multiple already-built models.