When you deploy a Next.js app with Incremental Static Regeneration (ISR), pages get regenerated on-demand after their cache expires. ISR lets you get the performance benefits of static generation while keeping your content fresh.

But there's a problem. When many users request the same ISR route at once and the cache is expired, each request can trigger its own function invocation. This is called a "cache stampede." It wastes compute, overloads your backend, and can cause downtime.

The Vercel CDN now prevents this with request collapsing . When multiple requests hit the same uncached path, only one request per region invokes a function. The rest wait and get the cached response.

Vercel automatically infers cacheability for each request through framework-defined infrastructure, configuring our globally distributed router.…