Table of Contents Layer 1 — Reactive Variable Caching (Vue Reactivity System) Layer 2 — Computed Property Caching & Memoization Layer 3 — Composable-Level Data Caching Layer 4 — Nuxt Data Fetching Cache ( useFetch / useAsyncData ) Layer 5 — Server Route Caching with Nitro Layer 6 — Route-Level Cache Rules ( routeRules ) Layer 7 — HTTP & Browser Caching Headers Layer 8 — Pinia as a Client-Side Cache Store Quick Reference Cheat Sheet Layer 1 — Reactive Variable Caching {#layer-1} Before we talk about network caches, let's talk about reactivity overhead — because creating unnecessary deep reactive proxies is a silent performance killer in large Vue apps. shallowRef and shallowReactive for large data By default, ref() and reactive() deeply proxy every nested property. For large API responses, table rows, or chart datasets this is wasteful — you're paying to track changes you'll never make.…