ISR
Incremental Static Regeneration: a Next.js feature that re-generates static pages in the background after a specified time interval, combining SSG speed with fresh data.
What is ISR?
Incremental Static Regeneration: a Next.js feature that re-generates static pages in the background after a specified time interval, combining SSG speed with fresh data.
ISR is a intermediate-level concept that sits in the Web & Content Delivery area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "ISR" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn ISR in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the ISR lessonRelated lessons
Lessons that touch on ISR as part of a larger topic.
Static Site Generation (SSG)
Pre-building HTML pages at build time, the fastest possible delivery for content that does not change per request
intermediate · web content delivery
Business Continuity Planning
Keep the business running during disruptions, beyond IT into organizational resilience
advanced · reliability resilience
See also
Related glossary terms you might want to look up next.
Static Site Generation (SSG)
Pre-rendering pages to static HTML at build time. The fastest possible page loads because there's no server-side computation on each request.
SSR
Server-Side Rendering: generating HTML on the server for each request. Slower than SSG but always returns fresh data. Good for personalized or frequently changing pages.
CDN
A network of servers distributed globally that caches content close to users. Netflix uses CDNs to stream video from servers near you, not from one central location.