PerformanceResourceTiming: serverTiming property

Baseline 2023

Newly available

Since March 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The serverTiming read-only property returns an array of PerformanceServerTiming entries containing server timing metrics.

Server timing metrics require the server to send the Server-Timing header. For example:

Server-Timing: cache;desc="Cache Read";dur=23.2

The serverTiming entries can live on navigation and resource entries.


An array of PerformanceServerTiming entries.


Logging server timing entries

You can use a PerformanceObserver to watch for PerformanceServerTiming entries. Each server entry's duration is logged to the console.

Example using a PerformanceObserver, which notifies of new resource performance entries as they are recorded in the browser's performance timeline. Use the buffered option to access entries from before the observer creation.

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    entry.serverTiming.forEach((serverEntry) => {
      console.log(`${} duration: ${serverEntry.duration}`);

["navigation", "resource"].forEach((type) =>
  observer.observe({ type, buffered: true }),

Example using Performance.getEntriesByType(), which only shows resource performance entries present in the browser's performance timeline at the time you call this method:

for (const entryType of ["navigation", "resource"]) {
  for (const { name: url, serverTiming } of performance.getEntriesByType(
  )) {
    if (serverTiming) {
      for (const { name, duration } of serverTiming) {
        console.log(`${url}: ${name} duration: ${duration}`);

Cross-origin server timing information

Access to server timing information is restricted to the same origin. To expose cross-origin timing information, the Timing-Allow-Origin HTTP response header needs to be set.

For example, to allow to see server timing information, the cross-origin resource should send:



Server Timing
# servertiming-attribute

Browser compatibility

BCD tables only load in the browser

See also