You can manage your team's testers and distribute builds to them using the Firebase console.
Before you begin
If you haven't already, add Firebase to your Android project.
If you aren't using any other Firebase products, you only have to create a project and register your app. However, if you decide to use additional products in the future, be sure to complete all of the steps on the page linked above.
Step 1. Build your app
When you're ready to distribute a pre-release version of your app to testers, build an APK using your normal process. You must sign the APK with your debug key or app signing key.
Step 2. Distribute your app to testers
To distribute your app to testers, upload the APK file using the Firebase console:
Open the App Distribution page of the Firebase console. Select your Firebase project when prompted.
On the Releases page, select the app you want to distribute from the drop-down menu.
Drag your app's APK file to the console to upload it.
When the upload completes, specify the tester groups and individual testers you want to receive the build. Then, add release notes for the build.
See Manage testers for more on creating tester groups.
Click Distribute to make the build available to testers.
Once you distribute your build, it becomes available in the App Distribution dashboard of the Firebase console for 150 days (five months). When the build is 30 days from expiring, an expiration notice appears in both the console and your tester's list of builds on their test device.
Testers who haven't been invited to test the app receive email invitations to get started, and existing testers receive email notifications that a new build is ready to test (read the tester set up guide for instructions on how to install the test app). You can monitor the status of each tester-whether they accepted the invitation and whether they downloaded the app-in the Firebase console.