Learn How To Test Across Browsers

For Cross Browser Testing, Screener provides access to Chrome and Firefox browsers and device emulation out-of-the-box. To test against additional browsers, Screener integrates with Sauce Labs to provide access to IE, Safari and Edge browsers.

By default, Screener runs tests against the Chrome browser, which does not require a Sauce account.

Important Notes about Cross Browser Testing with Sauce Labs:
  • Cross Browser Testing with Sauce Labs will be slower than regular Screener visual regression tests, and so it is not recommended to run on every commit.
  • You may want to limit cross browser testing to certain scenarios, such as only when merging into master (see example below).
  • Requirements: A valid Sauce Labs account, and access to enough concurrency in your Sauce account to run Screener tests. Each browser/resolution combination will use one concurrent machine.
  • Screener's auto-parallelization is disabled when using Sauce Labs browsers to reduce the number of concurrent browsers required in your Sauce account, unless sauce.maxConcurrent is set.

  1. Adding Browsers
  2. Adding Sauce Labs Browsers
  3. Supported Browsers

Adding Browsers

To test against multiple browsers, add the browsers option to your screener.config.js file:

// screener.config.js
module.exports = {
  browsers: [
      browserName: 'chrome',
      browserName: 'firefox'

Adding Sauce Labs Browsers

To test Internet Explorer, Safari or Edge browsers, a Sauce Labs account is required, and your Sauce credentials need to be added via the sauce option in your screener.config.js file. Browsers added must match one of the supported browsers/versions in the browser table below.

Here is a CircleCI example that only runs cross browser tests when committing into master branch:

var config = {
  // regular screener config
// only run cross browser tests when merging into 'master' branch
if (process.env.CIRCLE_BRANCH === 'master') {
  config.browsers = [
      browserName: 'chrome'
      browserName: 'internet explorer',
      version: '11.103'
      browserName: 'safari',
      version: '11.0'
  config.sauce = {
    username: 'sauce_user',
    accessKey: 'sauce_access_key',
    maxConcurrent: 10
module.exports = config;

Supported Browsers

chrome-do not set-
firefox-do not set-
internet explorer11.103requires Sauce Account
microsoftedge16.16299requires Sauce Account
safari11.0requires Sauce Account

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