What Is An LLM Router?

An LLM Router is a piece of software that directs prompts to different models. Instead of using always the same model for each request, the router redirects each query to a different model. LLM Routing is used mostly for 3 different purposes: Cost saving : Using a cheaper model when handling easy tasks Specialization : Use specialist models when needed Availability : Using fallback models when one is down or load balancing LLM Routers do the routing automatically so the user experience is smooth and without friction. They differ from LLM Gateways as those ones are more about managing the traffic, ensuring observability and governance rather than choosing the right model for the job. Rule-based routing vs AI-powered routing LLM Routers can be grouped into 2 different approaches: rule-based routers which are programmatic and AI-powered routers that use a model to do the redirect. Rule-based routers, like Manifest , are the simplest to implement: they are fast, deterministic and can run e