In-app purchase
Also called: IAP, Subscription
Buying digital content or features inside a mobile app, paid through the App Store or Google Play.
Definition
The store handles payment; the app unlocks the content. Testers use sandbox or license-tester accounts, never real money, and check restore, refunds and subscriptions.
In practice
Buying 'Premium yearly' in the app charges through Google Play and unlocks premium on all the user's devices.