What is Incremental Static Regeneration (ISR)?
A Next.js feature that updates static pages in the background without rebuilding the entire site.
ISR combines the speed of SSG with the freshness of SSR. Pages are served from cache, and when the cache expires (based on a revalidate interval), Next.js regenerates the page in the background. The next visitor gets the fresh version. This means you can have thousands of static pages that update without a full rebuild.