Vercel Adds Support for Next.js 16.3

Vercel now officially supports Next.js 16.3. This update introduces lighter prefetching, immutable static assets, and instant navigation, with the following improvements observed in upgraded applications:

• Prefetch requests decreased by an average of 45%, with some applications seeing reductions of over 70%.
• CDN requests for static content dropped by 17%, and transfer bytes decreased by 24%.
• Frequently deployed projects saw global TTFB improve by up to 60%, and p99 route resolution speed for large-scale sites became approximately 2x faster.

In Next.js 16.3, immutable static assets are enabled by default. Vercel deploys content-addressed static files using the /_next/static/immutable/* path, allowing them to be reused across deployments and ensuring browser caches persist after redeployment. By avoiding re-uploading unchanged assets, deployment times are reduced by an average of up to 30%.

To enhance routing performance, Vercel also improved the layer handling deployment path metadata. Previously, metadata for each segment was stored as individual cache entries; now, it is bundled into JSONL-format shards, with optimized in-process and remote caching reducing cache misses by approximately 10x.

This structure improves hit rates with fewer, larger cache entries while enabling CDNs to quickly locate required metadata within shards. Vercel explained that this improved p99 performance for large-scale Next.js applications in environments handling approximately 5 million metadata lookups per second.