Get started with StoreKit 2 for iOS

At WWDC21, Apple introduced a new version of StoreKit - StoreKit 2. The new in-app purchases API offers new features and improvements over the previous version, including async/await adaptation, more flexible payment options, improved testing and debugging tools.

In this article, we'll go though the StoreKit 2 API and learn how to use it to request in-app purchase products, how to purchase and validate them, how to restore in-app purchases, how to check user's entitlements and more.

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Configuring products

The first step of offering in-app purchases in an iOS app is to create products we'd like to offer.

We can do that through App Store Connect or through a local StoreKit configuration file for testing. To get up and running quickly, we can just use a local StoreKit configuration file for now.

Checkout this article on StoreKit testing in Xcode to get more details on how to setup a StoreKit configuration file.

Requesting products

After setting up the file, we can load the configured products to show them to the user.

To load available products, StoreKit 2 provides the following method:

let productIdentifiers = ["com.example.budget", "com.example.standard", " com.example.solidary"]
let products = try await Product.products(for: productIdentifiers)

Each Product has properties like displayName, description or displayPrice and more that we can directly use to show to the user.

If the product is an auto-renewable subscription, we can use the status and renewalInfo on the subscription property to provide users with appropriate informations about their subscription status.

Purchasing a product

If a user decides to purchase one of our products, we can call the purchase method on the selected product:

let result = try await product.purchase()

This method brings up a system confirmation sheet. The user can then confirm the purchase or cancel it.

The value of the purchase result represents the state of the purchase:

switch result {
case .success(let result):
    switch verificationResult {
    case .verified(let transaction):
        // Give the user access to purchased content.
        // Complete the transaction with transaction.finish()
    case .unverified(let transaction, let verificationError):
        // The purchase failed verification for the provided reason.
    }
case .pending:
    // The purchase is waiting for some user action.
    // Purchase may succeed in the future,
    // the resulting Transaction will be delivered via Transaction.updates
case .userCancelled:
    // The user cancelled the purchase.
default:
    break
}

Transactions & current entitlements

When offering paid content or features, we need to know which ones were already bought by a user to unlock them.

For that, StoreKit 2 provides access to current entitlements which lists all products the user is entitled to:

func refreshPurchasedProducts() async {
    for await result in Transaction.currentEntitlements {
        guard case .verified(let transaction) = result else { continue }
        if transaction.revocationDate == nil {
            self.purchasedProductIDs.insert(transaction.productID)
        } else {
            self.purchasedProductIDs.remove(transaction.productID)
        }
    }
}

Restoring in-app purchases

When users reinstall an iOS app or download it on a new device, we as developers need to make sure that all in-app purchases the user previously made are restored.

When it comes to restoring in-app purchases, Apple recommends doing it proactively, without the user taking any actions. This can be done by using the current entitlements described above.

Additionally, we can offer a restore in-app purchases button which calls AppStore.sync() to enforce the synchronisation of transaction information.

Check out this article to learn more on how to restore in-app purchases with StoreKit 2 .

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Check out my new book on preparing for a technical iOS job interview with over 200 questions & answers. Test your knowledge on iOS topics such as Swift & Objective-C, SwiftUI & UIKit, Combine, HTTP Networking, Authentication, Core Data, Concurrency with async/await, Security, Automated Testing and more.

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