Demo

Partial Fallbacks

High-cardinality sites can't pre-render every slug. Without generateStaticParams, every visit shows a Suspense fallback. With it, unknown slugs block while generating.
experimental.partialFallbacks gives unknown slugs an instant shell from CDN while dynamic data streams in. After the first visit, the page is upgraded to fully static.

next.config.ts

1const nextConfig = {
2  experimental: {
3    partialFallbacks: true,
4  },
5};

A product catalog with 9 products. Only 3 are in generateStaticParams.
Build-time products (1–3) load instantly with no fallback.
Request-time products (4–9) generate a unique slug per click, so you always see the streaming behavior. Visiting the same URL again loads instantly from cache.
An artificial 2 second delay makes the difference more noticeable.