Server-Timing response headers will pass through to the client

Vercel's CDN will begin passing through the Server-Timing response header to the client on August 10, 2026.

Use Server-Timing to report backend metrics like database query time and cache hits. These values appear in the browser's network panel and as PerformanceServerTiming entries through the Performance API.

If you want to keep the current behavior, where the header is stripped from every response, you can add a transform in vercel.json:

Learn more about the Performance API and Server Timing.

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