How to Build a Multi-Model LLM Fallback Layer Without Rewriting Your App (opens in new tab)

Most LLM integrations start as a single provider call. That is usually the right move. You pick one strong model, wire up a chat completions request, ship the feature, and learn from real users. The problem starts later. Your support assistant needs better latency. Your document workflow needs a larger context window. Your extraction job is too expensive on the flagship model. A provider returns rate-limit errors during a launch. A new model is cheaper for background tasks but not good enough...