Model router

Each AI company has its own API, pricing and account. A model router puts one doorway in front of them, so a developer connects once and can choose among models from many companies. If one model goes down, it can switch to another, and it can send easy requests to a cheaper model.

OpenRouter is the best-known example. Requests from a huge number of apps pass through a doorway like this, so it shows which models are actually used and how much. But it only covers the places that use that doorway, so it is not the same as total usage in the world.

It is like a delivery app that compares several courier companies at once. You do not sign up with each company, and if one is backed up, the package can go through another.

LastAI's "usage ranking" is built from the amount of tokens that passed through a doorway like this. It is a rare way to see what is actually used, not just test scores.