What is "testflight"

TestFlight is an online service for over-the-air installation and testing of mobile applications, currently owned by Apple Inc and only offered to developers within the iOS Developer Program. Developers signed up with the service to distribute applications to internal or external beta testers, who could subsequently send feedback about the application to developers. The TestFlight SDK additionally allowed developers to receive remote logs, crash reports and tester feedback.

TestFlight initially supported testing of Android and iOS applications, but since March 2014, Apple has retracted support for Android. As of 2015, applications must be published for TestFlight using Xcode, and testers must be invited using iTunes Connect. After invitation, up to 25 internal testers (with up to 10 devices each) and 2,000 external beta testers can download and test the application build. Up to 100 apps can be tested at a time, internally or externally. Testers may be grouped and separate builds created for each group. The TestFlight application for iOS notifies testers when new builds are available, features to focus on, and enables sending of feedback.