# Vercel — Preventing the stampede: Request collapsing in the Vercel CDN

- Company: Vercel (vercel.com)
- Announced: 2025-09-25T13:00:00+00:00
- Category: capability-change
- Coverage: not counted
- Announcement: yes
- Group: announcements
- Source: https://vercel.com/blog/cdn-request-collapsing
- Record: https://forck.live/items/20814-preventing-the-stampede-request-collapsing-in-the-vercel-cdn
- Subject: v0 / AI SDK / AI Gateway

Vercel added request collapsing to its CDN to prevent cache stampedes on ISR pages. When multiple requests hit the same uncached path, only one function invocation per region runs; other requests wait for the cached response. The system uses a two-level distributed lock (node-level and regional) and automatically determines cacheability through framework integration.

## Evidence

Verbatim from https://vercel.com/blog/cdn-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.

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Record: https://forck.live/items/20814-preventing-the-stampede-request-collapsing-in-the-vercel-cdn
Catalogue: https://forck.live/llms.txt
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