Server-Timing response headers will pass through to the client
Vercel's CDN will now pass through Server-Timing response headers to clients starting August 10, 2026, allowing backend metrics like database query time and cache hits to appear in browser network panels and Performance API. Users can preserve the previous behavior by adding a transform in vercel.json.
Vercel's CDN will begin passing through the response header to the client on August 10, 2026. Server-Timing
Use to report backend metrics like database query time and cache hits. These values appear in the browser's network panel and as entries through the Performance API.Server-TimingPerformanceServerTiming
If you want to keep the current behavior, where the header is stripped from every response, you can add a in :transformvercel.json
Learn more about the .Performance API and Server Timing
Source: original entry ↗