Next.js 15.4: Turbopack production builds validated and Next.js 16 previewed

Key update

Next.js 15.4 (July 14, 2025) advances Turbopack from fast-dev tooling to production-grade builds: next build --turbopack now passes the full integration test suite (all 8,298 tests) and Turbopack is being used to power vercel.com. The release also publishes an early preview of Next.js 16, which formalizes Turbopack builds for production (beta), unified caching primitives (cacheComponents), router optimizations, and a set of experimental flags you can enable today.

Why it matters

This is one of the clearest signals yet that a Rust-based bundler can replace legacy JS bundlers in large production sites: teams should expect significantly faster build times and more scalable dev tooling on large monorepos and CI pipelines once Turbopack’s production chunking and final bundling optimizations land. Practically, that means you should plan to: validate next build --turbopack in a dedicated CI job for a representative app, measure end-to-end build and deploy times, and test runtime behavior (especially third-party plugins and edge/Node runtimes). Because Next.js 16 will also deprecate older Node versions and introduce caching and prerendering changes, coordinate infra (Node versions, caching layers, and CD/CI caches) before flipping defaults. If you rely on custom bundler plugins or uncommon Next.js config options, treat this as an integration project rather than a drop-in swap — expect to iterate on config, watch for production chunking fixes called out by the team, and use the canary channel or feature flags to stage changes.

Source

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