Next.js 16.3 and Turbopack: What Really Changes in Production

Next.js 16.3 makes Turbopack the default bundler for production builds. The most impactful change isn't initial compilation speed — though it improves 55-75% for large projects — but persistent cache between consecutive builds, which directly reduces CI/CD costs. Turbopack's invalidation works at function level, not file level: changing a helper function only recompiles modules that directly import it. For teams running 40+ builds per day, the productivity gain from shorter wait times outweighs the compute savings.