Recap: Where This FitsPart 1 of this series covered exact-match caching: hashing the full request and returning a stored response when a new request matches an old one exactly. That layer is fast and safe, but it only helps when the input matches exactly, which is common for templated traffic and rare in open conversation. This article covers the layer that closes that gap: semantic caching. Part 3 covers what happens once a request actually reaches the model: self-hosted KV cache reuse and provider prefix caching, plus the production details: watching your metrics, working out your costs, and a full checklist.