Model Routing for Cost Efficiency: A Practical Guide

LLM routing policies that reduce inference cost without breaking vertical workflows in production.

Teams searching for model routing for cost efficiency usually already feel the pain: inference spend climbing faster than revenue, or RAG quality drifting after launch. This note is part of the GPU Bill Bodyguard series — practical infrastructure thinking for vertical AI founders.

Start with workflow-level attribution

Blended cloud bills hide the real problem. Name the workflows users actually run — detection, retrieval, generation, re-ranking — and attribute tokens and dollars to each. Until that exists, "cheaper models" is guesswork.

Route to the cheapest capable model

LLM routing is not vanity failover. It is a policy: for this vertical step, which model clears your quality bar at the lowest cost and latency? That policy belongs in infrastructure, not scattered across application code.

RAG is an operations problem

Production RAG fails when freshness, eval coverage, and retrieval quality are treated as launch-week tasks. Gateways that only proxy HTTP do not fix stale corpora or missing eval hooks.