Preview Changes in Your Web Editor

Have you ever launched an application in your codespace only for the running application to get lost in a sea of browser tabs? Today we're announcing the ability to preview your running application directly in your web editor.

Update your Preview URL

Supporting this feature required a change to the URL of previewed applications from to This is potentially a breaking change. If you rely on a preview url in any project you will need to update your code to reflect the new URL format.

Alternatively, the environment variable GITHUB_CODESPACES_PORT_FORWARDING_DOMAIN gives you access to the domain that your application will forward to. This will enable you to code in this variable anywhere you have hard-coded the preview URL.