Model Routing Across Models and Hardware Tiers
One model for every request is a rounding error away from malpractice. Requests are not uniform; they range from trivial to hard, from latency-critical to background. A router treats the model fleet as a portfolio and sends each request to the cheapest resource that can satisfy it. Route across models, from small and fast to large and capable, and most traffic never touches the flagship. Route across hardware tiers, from newest accelerators to older silicon, and expensive capacity is reserved for work that needs it. Routing is the highest-return control in the stack because it changes what fraction of demand hits your most expensive resource. The model is a commodity input; the router is the margin engine.
Knowledge check
What does a model router optimize, and why does it produce outsized cost savings?
Show the answer
A router optimizes the match between each request's difficulty and the cheapest model or hardware tier that can meet the required quality and latency. Savings are outsized because request difficulty is highly skewed: most requests are easy, so routing the easy majority to small, cheap resources reserves expensive flagship capacity for the hard minority, cutting blended cost per request substantially.