How does incremental static regeneration let you get the benefits of both static pages and fresh content?

Incremental static regeneration serves the existing fast, cached static page to visitors while a new version is being generated in the background after the revalidation period passes, so the current visitor never waits for a rebuild, and the next visitor after that automatically sees the updated content once it is ready.

// This page will regenerate at most once every 300 seconds
const res = await fetch('https://api.example.com/products', {
  next: { revalidate: 300 }
});