# Server\-Timing response headers will pass through to the client

**Published:** July 30, 2026 | **Authors:** Tim Caswell, Steven Salat

---

On August 10, 2026, Vercel's CDN will stop stripping the [Server-Timing](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Server-Timing) response header and begin passing it through to the client.

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](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceServerTiming) entries through the Performance API.

```text
Server-Timing: db;desc="Database";dur=53,cache;desc="Cache";dur=4.2
```

If you want to keep the current behavior, where the header is stripped from every response, you can add a [transform](https://vercel.com/docs/project-configuration/vercel-json#transform-object-definition) in `vercel.json`:

```json
{
  "$schema": "https://openapi.vercel.sh/vercel.json",
  "routes": [
    {
      "src": "/(.*)",
      "transforms": [
        {
          "type": "response.headers",
          "op": "delete",
          "target": {
            "key": "server-timing"
          }
        }
      ]
    }
  ]
}
```

Learn more about the [Performance API and Server Timing](https://developer.mozilla.org/en-US/docs/Web/API/Performance_API/Server_timing).

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