Hi there, This is excerpt from Apple’s testflight site. Seems like you can do it from the link in your email. Opting Out If you do not accept your email invitation, the beta app will not be installed and you will not be listed as a tester. Additionally, you can unsubscribe using the link at the bottom of the invitation email to notify the developer that you’d like to be removed from their list. If you accepted the invitation and no longer wish to test the app, you can delete yourself as a tester in the app’s Information page in TestFlight by tapping Stop Testing. Here is the link: https://testflight.apple.com/ Cheers