What Is Incremental Static Regeneration (ISR) with a CMS?
IntermediateQuick Answer
TL;DR
Incremental Static Regeneration (ISR) combines the performance of static site generation with the flexibility of dynamic content. Pages are pre-built and served from a CDN at static speed, but they regenerate in the background after a set time interval or immediately when content changes. Visitors always get a fast, cached page while updates propagate in seconds — no full site rebuild required.
Key Takeaways
- ISR serves pre-built static pages from a CDN while regenerating stale pages in the background
- Regeneration can be time-based (every N seconds) or on-demand (triggered by a webhook)
- Only affected pages rebuild — not the entire site — making updates near-instant at scale
- ISR eliminates the rebuild bottleneck that makes pure SSG impractical for large or frequently updated sites