In-App Purchase lets people buy digital products within your app, in a store that you design.
For example, users might:
Upgrade a basic version of an app to a premium version
Renew a subscription for new monthly content
Purchase virtual items, such as a new level or weapon in a game
Buy and download new books
You use the StoreKit framework to embed a store in your app and support In-App Purchase. When a user makes a purchase, StoreKit connects to the App Store to securely process the payment and then notifies your app so that it can provide the purchased item.
The following guidelines can help you design a purchasing experience that users appreciate.
Elegantly integrate the store experience into your app. When presenting products and handling user transactions, create an experience that feels at home in your app. You don’t want users to think that they’ve entered a different app when they visit your store.
Use simple, succinct titles and descriptions. It’s best when people can scan a set of items and quickly find the ones they’re interested in. When you use plain, direct language and titles that don’t truncate or wrap, it’s easier for people to understand the items you’re offering.
Don’t alter the default confirmation alert. When users buy a product, StoreKit presents a confirmation alert (shown above). You shouldn’t modify this alert because it helps users avoid accidental purchases.