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dpearson2699/swift-ios-skills2.7k installs

storekit

Implement, review, or improve in-app purchases and subscriptions using StoreKit 2. Use when building paywalls with SubscriptionStoreView or ProductView, processing transactions with Product and Transaction APIs, verifying entitlements, handling purchase flows (consumable, non-consumable, auto-renewable), implementing offer codes or promotional/win-back/introductory offers, managing subscription status and renewal state, setting up StoreKit testing with configuration files, or integrating Family Sharing, Ask to Buy, refund handling, and billing retry logic.

How do I install this agent skill?

npx skills add https://github.com/dpearson2699/swift-ios-skills --skill storekit
view source ↗

Is this agent skill safe to install?

  • Gen Agent Trust Hubpass

    This skill provides comprehensive guidance and code examples for implementing StoreKit 2 in iOS applications. It follows Apple's security best practices, such as transaction verification and handling revoked purchases, with no malicious patterns detected.

  • Socketpass

    No alerts

  • Snykwarn

    Risk: MEDIUM · 1 issue

  • ZeroLeakspass

    Score: 93/100 · 2 sections analyzed

What does this agent skill do?

StoreKit 2 In-App Purchases and Subscriptions

Implement in-app purchases, subscriptions, paywalls, and StoreKit testing using StoreKit 2. Use the modern Swift-based Product, Transaction, PurchaseAction, StoreView, and SubscriptionStoreView APIs. Avoid original In-App Purchase APIs (SKProduct, SKPaymentQueue) unless legacy OS support requires them.

StoreKit views initiate purchases automatically. For custom controls, use PurchaseAction in SwiftUI, purchase(confirmIn:options:) in UIKit/AppKit, and product.purchase(options:) on watchOS.

Contents

Product Types

TypeEnum CaseBehavior
Consumable.consumableUsed once, can be repurchased (gems, coins)
Non-consumable.nonConsumablePurchased once permanently (premium unlock)
Auto-renewable.autoRenewableRecurring billing with automatic renewal
Non-renewing.nonRenewingTime-limited access without automatic renewal

Loading Products

Define product IDs as constants. Fetch products with Product.products(for:).

import StoreKit

enum ProductID {
    static let premium = "com.myapp.premium"
    static let gems100 = "com.myapp.gems100"
    static let monthlyPlan = "com.myapp.monthly"
    static let yearlyPlan = "com.myapp.yearly"
    static let all: [String] = [premium, gems100, monthlyPlan, yearlyPlan]
}

let products = try await Product.products(for: ProductID.all)
for product in products {
    print("\(product.displayName): \(product.displayPrice)")
}

Purchase Flow

Prefer StoreKit views for standard paywalls because they initiate purchases, restore purchases, and display policy controls. For custom SwiftUI purchase buttons, prefer PurchaseAction from the environment. Use direct product.purchase(options:) for watchOS, and use purchase(confirmIn:options:) for UIKit or AppKit confirmation. Always handle every PurchaseResult, verify before access, deliver durably, then finish.

@Environment(\.purchase) private var purchase

func purchaseProduct(_ product: Product) async throws {
    let result = try await purchase(product, options: [
        .appAccountToken(userAccountToken)
    ])
    switch result {
    case .success(let verification):
        let transaction = try checkVerified(verification)
        await deliverContent(for: transaction)
        await transaction.finish()
    case .userCancelled:
        break
    case .pending:
        // Ask to Buy or deferred approval: show pending UI, no unlock yet.
        showPendingApprovalMessage()
    @unknown default:
        break
    }
}

func checkVerified<T>(_ result: VerificationResult<T>) throws -> T {
    switch result {
    case .verified(let value): return value
    case .unverified(_, let error): throw error
    }
}

Transaction.updates Listener

Start at app launch, not when a paywall appears. Catches purchases from other devices, Family Sharing changes, renewals, Ask to Buy approvals, refunds, revocations, and unfinished transactions Apple emits once immediately after launch. Keep the task retained for the app lifetime.

@main
struct MyApp: App {
    private let transactionListener: Task<Void, Never>

    init() {
        transactionListener = Self.listenForTransactions()
    }

    var body: some Scene {
        WindowGroup { ContentView() }
    }

    static func listenForTransactions() -> Task<Void, Never> {
        Task(priority: .background) {
            for await result in Transaction.updates {
                guard case .verified(let transaction) = result else { continue }
                await StoreManager.shared.updateEntitlements()
                await transaction.finish()
            }
        }
    }
}

Entitlement Checking

Transaction.currentEntitlements emits non-consumables, active or grace-period auto-renewable subscriptions, and the latest non-renewing subscription transaction—including finished ones. It excludes consumables and refunded or revoked products. Track consumable fulfillment separately, and apply the app's expiration policy to non-renewing subscriptions before granting access.

@Observable
@MainActor
class StoreManager {
    static let shared = StoreManager()
    var purchasedProductIDs: Set<String> = []
    var isPremium: Bool { purchasedProductIDs.contains(ProductID.premium) }

    func updateEntitlements() async {
        var purchased = Set<String>()
        for await result in Transaction.currentEntitlements {
            if case .verified(let transaction) = result,
               transaction.revocationDate == nil {
                if transaction.productType == .nonRenewing,
                   transaction.expirationDate.map({ $0 <= .now }) ?? true {
                    continue
                }
                purchased.insert(transaction.productID)
            }
        }
        purchasedProductIDs = purchased
    }
}

SwiftUI .currentEntitlementTask Modifier

struct PremiumGatedView: View {
    @State private var state: EntitlementTaskState<VerificationResult<Transaction>?> = .loading

    var body: some View {
        Group {
            switch state {
            case .loading: ProgressView()
            case .failure: PaywallView()
            case .success(.some(.verified(let transaction))) where transaction.revocationDate == nil:
                PremiumContentView()
            case .success:
                PaywallView()
            }
        }
        .currentEntitlementTask(for: ProductID.premium) { state in
            self.state = state
        }
    }
}

SubscriptionStoreView (iOS 17+)

Built-in SwiftUI view for subscription paywalls. Handles product loading, purchase UI, and restore purchases automatically.

SubscriptionStoreView(groupID: "YOUR_GROUP_ID")
    .subscriptionStoreControlStyle(.prominentPicker)
    .subscriptionStoreButtonLabel(.multiline)
    .storeButton(.visible, for: .restorePurchases)
    .storeButton(.visible, for: .redeemCode)
    .subscriptionStorePolicyDestination(url: termsURL, for: .termsOfService)
    .subscriptionStorePolicyDestination(url: privacyURL, for: .privacyPolicy)
    .onInAppPurchaseCompletion { product, result in
        if case .success(.success(.verified(let transaction))) = result {
            await deliverContent(for: transaction)
            await transaction.finish()
        }
    }

Custom Marketing Content

Use the container background and header patterns in SubscriptionStoreView Control Styles.

Hierarchical Layout

Use SubscriptionOptionGroup, SubscriptionOptionSection, or SubscriptionPeriodGroupSet to organize iOS 18+ options; see Subscription Group Management.

StoreView (iOS 17+)

Merchandises multiple products with localized names, prices, and purchase buttons.

StoreView(ids: [ProductID.gems100, ProductID.premium], prefersPromotionalIcon: true)
    .productViewStyle(.large)
    .storeButton(.visible, for: .restorePurchases)
    .onInAppPurchaseCompletion { product, result in
        if case .success(.success(.verified(let transaction))) = result {
            await deliverContent(for: transaction)
            await transaction.finish()
        }
    }

ProductView for Individual Products

ProductView(id: ProductID.premium) { iconPhase in
    switch iconPhase {
    case .success(let image): image.resizable().scaledToFit()
    case .loading: ProgressView()
    default: Image(systemName: "star.fill")
    }
}
.productViewStyle(.large)

Subscription Status Checking

func checkSubscriptionActive(groupID: String) async throws -> Bool {
    let statuses = try await Product.SubscriptionInfo.status(for: groupID)
    for status in statuses {
        guard case .verified = status.renewalInfo,
              case .verified = status.transaction else { continue }
        if status.state == .subscribed || status.state == .inGracePeriod {
            return true
        }
    }
    return false
}

Renewal States

StateMeaning
.subscribedActive subscription
.expiredSubscription has expired
.inBillingRetryPeriodPayment failed, Apple is retrying
.inGracePeriodPayment failed but access continues during grace period
.revokedApple refunded or revoked the subscription

Restore Purchases

StoreKit 2 handles restoration via Transaction.currentEntitlements. Add a restore button or call AppStore.sync() explicitly.

func restorePurchases() async throws {
    try await AppStore.sync()
    await StoreManager.shared.updateEntitlements()
}

On store views: .storeButton(.visible, for: .restorePurchases)

App Transaction (App Purchase Verification)

Verify the legitimacy of the app installation. Use for business model changes or detecting tampered installations (iOS 16+).

func verifyAppPurchase() async {
    do {
        let result = try await AppTransaction.shared
        switch result {
        case .verified(let appTransaction):
            let originalVersion = appTransaction.originalAppVersion
            let purchaseDate = appTransaction.originalPurchaseDate
            // Migration logic for users who paid before subscription model
        case .unverified:
            // Potentially tampered -- restrict features as appropriate
            break
        }
    } catch { /* Could not retrieve app transaction */ }
}

Purchase Options

// App account token for server-side reconciliation
try await product.purchase(options: [.appAccountToken(UUID())])

// Consumable quantity
try await product.purchase(options: [.quantity(5)])

// Simulate Ask to Buy in sandbox
try await product.purchase(options: [.simulatesAskToBuyInSandbox(true)])

SwiftUI Purchase Callbacks

.onInAppPurchaseStart { product in
    await analytics.trackPurchaseStarted(product.id)
}
.onInAppPurchaseCompletion { product, result in
    if case .success(.success(.verified(let transaction))) = result {
        await deliverContent(for: transaction)
        await transaction.finish()
    }
}
.inAppPurchaseOptions { product in
    [.appAccountToken(userAccountToken)]
}

Common Mistakes

1. Not starting Transaction.updates at app launch

// WRONG: No listener -- misses renewals, refunds, Ask to Buy approvals
@main struct MyApp: App {
    var body: some Scene { WindowGroup { ContentView() } }
}
// CORRECT: Start listener in App init (see Transaction.updates section above)

2. Forgetting transaction.finish()

// WRONG: Never finished -- reappears in unfinished queue forever
let transaction = try checkVerified(verification)
unlockFeature(transaction.productID)

// CORRECT: Deliver durably, then finish. If delivery fails, do not finish yet.
let transaction = try checkVerified(verification)
try await recordDelivery(transaction)
await transaction.finish()

3. Ignoring verification result

// WRONG: Using unverified transaction -- security risk
let transaction = verification.unsafePayloadValue

// CORRECT: Verify before using
let transaction = try checkVerified(verification)

4. Using original In-App Purchase APIs in new StoreKit 2 code

// AVOID: Original In-App Purchase APIs
let request = SKProductsRequest(productIdentifiers: ["com.app.premium"])
SKPaymentQueue.default().add(payment)

// PREFERRED: StoreKit 2
let products = try await Product.products(for: ["com.app.premium"])
let result = try await product.purchase()

5. Not checking revocationDate

// WRONG: Grants access to refunded purchases
if case .verified(let transaction) = result {
    purchased.insert(transaction.productID)
}

// CORRECT: Skip revoked transactions
if case .verified(let transaction) = result, transaction.revocationDate == nil {
    purchased.insert(transaction.productID)
}

6. Hardcoding prices

// WRONG: Wrong for other currencies and regions
Text("Buy Premium for $4.99")

// CORRECT: Localized price from Product
Text("Buy \(product.displayName) for \(product.displayPrice)")

7. Not handling .pending purchase result

// WRONG: Silently drops pending Ask to Buy
default: break

// CORRECT: Explain approval is pending; unlock only after Transaction.updates
case .pending:
    showPendingApprovalMessage()

8. Checking entitlements only once at launch

// WRONG: Check once, never update
func appDidFinish() { Task { await updateEntitlements() } }

// CORRECT: Re-check on Transaction.updates AND on foreground return
// Transaction.updates listener handles mid-session changes.
// Also use .task { await storeManager.updateEntitlements() } on content views.

9. Missing restore purchases button

// WRONG: No restore option -- App Store rejection risk
SubscriptionStoreView(groupID: "group_id")

// CORRECT
SubscriptionStoreView(groupID: "group_id")
    .storeButton(.visible, for: .restorePurchases)

10. Subscription views without policy links

// WRONG: No terms or privacy policy
SubscriptionStoreView(groupID: "group_id")

// CORRECT
SubscriptionStoreView(groupID: "group_id")
    .subscriptionStorePolicyDestination(url: termsURL, for: .termsOfService)
    .subscriptionStorePolicyDestination(url: privacyURL, for: .privacyPolicy)

Review Checklist

  • Transaction.updates listener starts at app launch in App init
  • All transactions verified before granting access
  • transaction.finish() called only after durable content delivery
  • Revoked/refunded transactions excluded and entitlement state updated
  • .pending result shows Ask to Buy/deferred-approval feedback
  • Restore purchases button visible on paywall and store views
  • Terms of Service and Privacy Policy links on subscription views
  • Prices shown using product.displayPrice, never hardcoded
  • Subscription terms (price, duration, renewal) clearly displayed
  • Free trial states post-trial pricing clearly
  • No original In-App Purchase APIs (SKProduct, SKPaymentQueue) unless legacy OS support requires them
  • Product IDs defined as constants, not scattered strings
  • StoreKit tests cover promotional offers, win-back, offer codes, Ask to Buy, renewals, refunds, and revocations
  • Entitlements re-checked on Transaction.updates and app foreground
  • Server-side validation uses jwsRepresentation if applicable
  • Consumables delivered and finished promptly
  • Transaction observer types and product model types are Sendable when shared across concurrency boundaries

References

Add the canonical catalog link to the repository README so users can inspect current installs and available audits. The publishing guide covers the complete discovery path.

<a href="https://skillzs.dev/skills/dpearson2699/swift-ios-skills/storekit">View storekit on skillZs</a>