PerformanceServerTiming

Note: This feature is available in Web Workers

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

The PerformanceServerTiming interface surfaces server metrics that are sent with the response in the Server-Timing HTTP header.

This interface is restricted to the same origin, but you can use the Timing-Allow-Origin header to specify the domains that are allowed to access the server metrics. Note that this interface is only available in secure contexts (HTTPS) in some browsers.

Properties

PerformanceServerTiming.descriptionRead only

A string value of the server-specified metric description, or an empty string.

PerformanceServerTiming.durationRead only

A double that contains the server-specified metric duration, or value 0.0.

PerformanceServerTiming.nameRead only

A string value of the server-specified metric name.

Methods

PerformanceServerTiming.toJSON()

Returns a string that is the JSON representation of the PerformanceServerTiming object.

Example

Given a server that sends the Server-Timing header, for example a Node.js server like this:

const http = require('http');

function requestHandler(request, response) {
  const headers = {
    'Server-Timing': `
      cache;desc="Cache Read";dur=23.2,
      db;dur=53,
      app;dur=47.2
    `.replace(/\n/g, '')
  };
  response.writeHead(200, headers);
  response.write('');
  return setTimeout(_ => {
   response.end();
 }, 1000)
};

http.createServer(requestHandler).listen(3000).on('error', console.error);

The PerformanceServerTiming entries are now observable from JavaScript via the PerformanceResourceTiming.serverTiming property:

let entries = performance.getEntriesByType('resource');
console.log(entries[0].serverTiming);
// 0: PerformanceServerTiming {name: "cache", duration: 23.2, description: "Cache Read"}
// 1: PerformanceServerTiming {name: "db", duration: 53, description: ""}
// 2: PerformanceServerTiming {name: "app", duration: 47.2, description: ""}

Specifications

Specification
Server Timing
# the-performanceservertiming-interface

Browser compatibility

BCD tables only load in the browser

See also