Cross-browser Visual Testing

Learn how to effortlessly see visual changes across different browsers

Cross-browser visual testing is available for all Percy customers to effortlessly see visual changes across different browsers. Percy currently supports the latest versions of modern browsers, including Chrome, Firefox, Edge, and Safari. Our custom rendering infrastructure automatically manages browser upgrades, versioning, and maintenance every quarter.

Percy runs visual tests for all the browsers that are enabled for the project on the Percy dashboard. You can also set the browser version by integrating your test with BrowserStack SDK with Automate. This allows you to configure various browser names and versions using Automate capability builder.

How it works

Because Percy stores the original DOM snapshot and page assets, we simply render the same page within different browsers when generating screenshots. This is handled entirely server-side and has no effect on the speed of your CI run since all rendering and diffing takes place in Percy, like normal.

When cross-browser testing is enabled, each build will show separate screenshots for each browser, highlighting the visual diffs specific to each. The number of diffs for each browser will appear over the browser icon on your build.

Keep in mind that you will occasionally see different visual diff counts for each browser because each renders slightly differently. Catching those browser-specific visual regressions is an advantage of cross-browser testing.

Enabling and disabling browsers

By default, Chrome, Firefox, Edge and Safari are enabled for each new project. Browsers can be enabled or disabled for any individual project at any time.

To enable or disable a browser, you will get the “browsers selection” option available in the created Project Settings.

1. Create a new Percy project and select “Percy” in Browser Selection to be handled by settings.
2. Click the Browsers tab. Select browsers to handle cross-browser testing for captured snapshots.

After enabling a browser, a new baseline will be established on the project’s subsequent build. This means that the snapshots in the first build for that browser won’t have a baseline comparison. Read more about our baseline picking logic.

If you disable a browser and choose to re-enable it in the future, we will update the browser to Percy’s newest version and the subsequent build will create a new baseline for that browser.

Browser versions

You can check the browser version information by clicking on the information icon, as shown below:

Usage

Each browser counts as a separate screenshot that counts towards your monthly screenshot usage. For example, a snapshot of your homepage in both Chrome and Firefox will count as 2 screenshots.