Next.js 16.3 is now available in a stable release. Compared to version 16.2, the React framework uses up to 90 percent less RAM when the Turbopack bundler runs in the dev mode next dev. Two features are now enabled by default: Disk Caching and Memory Eviction, both previously testable in a preview release from June this year.

With Disk Caching, the Rust-based bundler no longer keeps build artifacts permanently in memory but writes them to disk and reloads them only when needed. Memory Eviction automatically removes unused data from RAM, preventing builds from crashing with the notorious "FATAL ERROR" out-of-memory message.

The Next.js team cites two benchmarks in which Turbopack compiled 50 endpoints each: in one case memory usage dropped from 21.5 GB to 2 GB (about 90 percent less), in the other from 4.5 GB to 840 MB (around 82 percent). Users report similar improvements in their own projects.

Dev-mode apps gain further optimizations: faster server-side rendering now using Node streams directly, improved asset caching, and faster TypeScript checks. To run checks with TypeScript 7, developers install it via pnpm add -D typescript@^7 and enable the flag experimental.useTypeScriptCli: true, since TypeScript 7 does not yet fully support the programmatic JavaScript API.

The new Instant Navigations feature starts page transitions without visible delay: Next.js 16.3 prepares the relevant data paths ahead of the click via Server Components, Suspense, and the new use cache model, so no data refetching or component rebuilding is needed during navigation.

An experimental Rust-based React compiler also ships in 16.3. Instead of running through Babel in Node.js, it runs directly inside Turbopack, eliminating extra code generation and re-reading. According to the team, compiling large apps such as Vercel's AI coding assistant v0 is significantly faster, cutting the time from starting next dev to a fully loaded page by up to 46 percent. It is enabled in the Next.js config with reactCompiler: true and experimental.turbopackRustReactCompiler: true.