---
type: Glossary Term
title: "Incremental Static Regeneration (ISR)"
description: "A hybrid where pages are static-served from cache but regenerated on demand or on a TTL."
resource: "https://prerendering.com/glossary/isr"
tags: [rendering, glossary]
timestamp: 2026-05-11T00:00:00Z
---

# Incremental Static Regeneration (ISR)

A hybrid where pages are static-served from cache but regenerated on demand or on a TTL.

ISR serves cached static HTML and regenerates pages in the background when they hit a TTL or are explicitly invalidated. The first request after expiry triggers a regeneration; subsequent requests hit the fresh cache. Used to combine SSG-grade TTFB with SSR-grade freshness on content sites larger than 10,000 pages where SSG build times become impractical.

Also known as: ISR.

## Related

- [Next.js Rendering Decisions for SEO and AI Visibility](/blog/nextjs-rendering-decisions-for-seo-and-ai-visibility.md)