Next.js 16.3 is a major framework update introducing Instant Navigations — an opt-in suite bringing SPA-like responsiveness to server-driven apps via Partial Prefetching, improved ISR, a Navigation Inspector DevTools panel, and a Playwright test helper. General improvements include up to 90% less dev server RAM usage via Turbopack memory eviction, 5.5x faster CI builds with filesystem caching, 22% more SSR throughput via native Node.js streams, TypeScript 7 support for 10x faster type checking, versioned docs for AI coding agents, bundled prefetch requests, immutable static asset caching, and custom error boundaries with server retry. Experimental features include a Rust-based React Compiler (34–46% faster cold/warm builds) and network resilience with offline support.
