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Browser Launchers: Browserstack

Browser launchers for web test runner to run tests remotely on Browserstack.

For modern browsers, we recommend using other browser launchers, as they are a lot faster. Browserstack is a good option for testing on older browser versions.


Install the package:

npm i --save-dev @web/test-runner-browserstack

Add the browser launcher to your web-test-runner.confg.mjs:

import { browserstackLauncher } from '@web/test-runner-browserstack';

// options shared between all browsers
const sharedCapabilities = {
  // your username and key for browserstack, you can get this from your browserstack account
  // it's recommended to store these as environment variables
  'browserstack.user': process.env.BROWSER_STACK_USERNAME,
  'browserstack.key': process.env.BROWSER_STACK_ACCESS_KEY,

  project: 'my project',
  name: 'my test',
  // if you are running tests in a CI, the build id might be available as an
  // environment variable. this is useful for identifying test runs
  // this is for example the name for github actions
  build: `build ${process.env.GITHUB_RUN_NUMBER || 'unknown'}`,

export default {
  // how many browsers to run concurrently in browserstack. increasing this significantly
  // reduces testing time, but your subscription might limit concurrent connections
  concurrentBrowsers: 2,
  // amount of test files to execute concurrently in a browser. the default value is based
  // on amount of available CPUs locally which is irrelevant when testing remotely
  concurrency: 6,
  browsers: [
    // create a browser launcher per browser you want to test
    // you can get the browser capabilities from the browserstack website
      capabilities: {
        browserName: 'Chrome',
        os: 'Windows',
        os_version: '10',

      capabilities: {
        browserName: 'Safari',
        browser_version: '11.1',
        os: 'OS X',
        os_version: 'High Sierra',

      capabilities: {
        browserName: 'IE',
        browser_version: '11.0',
        os: 'Windows',
        os_version: '7',


The Browserstack launcher takes two properties, capabilities and localOptions.

capabilities are the selenium capabilities used to configure the browser to launch in Browserstack. You can generate most of these on the Saucelabs. It must contain a browserstack.user and browserstack.key property to authenticate with Browserstack, as well as name, build and project to identify the test run.

localOptions are options to configure the browserstack-local proxy. For most use cases, you don't need to configure this property.