storekit

SKILL.md

StoreKit 2 In-App Purchases and Subscriptions

Implement in-app purchases, subscriptions, paywalls, and StoreKit testing using
StoreKit 2 on iOS 26+. 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.

When reviewing StoreKit code, explicitly separate "preferred SwiftUI path" from
"invalid API": PurchaseAction is the preferred custom SwiftUI button path, but
direct product.purchase(options:) is still valid for lower-level custom
StoreKit flows.

Contents

Implementation Review Minimums

Product Types

Loading Products

Purchase Flow

Transaction.updates Listener

Entitlement Checking

SubscriptionStoreView (iOS 17+)

StoreView (iOS 17+)

Subscription Status Checking

Restore Purchases

App Transaction (App Purchase Verification)

Purchase Options

SwiftUI Purchase Callbacks

Common Mistakes

Review Checklist

References

Implementation Review Minimums

When reviewing a paywall, purchase manager, or entitlement gate, include these
points explicitly:

Standard SwiftUI paywalls should prefer StoreView, ProductView, or
SubscriptionStoreView; custom SwiftUI buy buttons should prefer
PurchaseAction; direct product.purchase(options:) is valid for
lower-level custom StoreKit flows.

Transaction.updates must start at app launch because it catches purchases
from other devices, Family Sharing changes, renewals, Ask to Buy approvals,
refunds, revocations, and unfinished transactions.

Include this entitlement-scope sentence verbatim when reviewing
Transaction.currentEntitlements: "It covers non-consumables, active or
grace-period auto-renewable subscriptions, and non-renewing subscriptions; it
does not include consumable purchase or delivery history."

Verify every VerificationResult before granting access. Deliver or persist
the entitlement first, then call transaction.finish().

Pending purchases and user cancellations never unlock content; pending Ask to
Buy approvals unlock only after a verified transaction arrives through the
launch-time listener.

Exclude refunded or revoked transactions from active entitlement state and
re-check entitlements when refunds or revocations arrive through
Transaction.updates.

Provide a visible restore purchases path and Terms of Service / Privacy
Policy links on subscription paywalls.

Product Types

Type
Enum Case
Behavior

Consumable
.consumable
Used once, can be repurchased (gems, coins)

Non-consumable
.nonConsumable
Purchased once permanently (premium unlock)

Auto-renewable
.autoRenewable
Recurring billing with automatic renewal

Non-renewing
.nonRenewing
Time-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:) only for lower-level custom flows, and use
purchase(confirmIn:options:) for UIKit or AppKit confirmation. Always handle
every PurchaseResult, verify before access, deliver durably, then finish.

Review wording: do not call product.purchase(options:) inherently wrong. Say
"prefer PurchaseAction for SwiftUI buttons; keep product.purchase(options:)
for lower-level custom flows that need direct StoreKit control."

@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.

In implementation reviews, name the launch-time coverage explicitly: purchases
made on other devices, Family Sharing changes, subscription renewals, Ask to Buy
approvals, refunds, revocations, and unfinished transactions.

@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

Use Transaction.currentEntitlements for non-consumables, active or grace
period auto-renewable subscriptions, and non-renewing subscriptions. It excludes
consumables and consumable delivery history; track consumable fulfillment in
your own app or server ledger. It also excludes refunded or revoked
transactions. Use Transaction.unfinished for unfinished consumables and
recovery sweeps. Always check revocationDate when processing transactions.

In reviews, include this sentence verbatim: "Transaction.currentEntitlements
covers non-consumables, active or grace-period auto-renewable subscriptions, and
non-renewing subscriptions; it does not include consumable purchase or delivery
history." Do not replace this with only a code sample or a revocation check.

@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 {
                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

SubscriptionStoreView(groupID: "YOUR_GROUP_ID") {
    VStack {
        Image(systemName: "crown.fill").font(.system(size: 60)).foregroundStyle(.yellow)
        Text("Unlock Premium").font(.largeTitle.bold())
        Text("Access all features").foregroundStyle(.secondary)
    }
}
.containerBackground(.blue.gradient, for: .subscriptionStore)

Hierarchical Layout

SubscriptionOptionGroup, SubscriptionOptionSection, and
SubscriptionPeriodGroupSet are iOS 18+ helper views for organizing options
inside SubscriptionStoreView.

SubscriptionStoreView(groupID: "YOUR_GROUP_ID") {
    SubscriptionPeriodGroupSet()
}
.subscriptionStoreControlStyle(.picker)

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

State
Meaning

.subscribed
Active subscription

.expired
Subscription has expired

.inBillingRetryPeriod
Payment failed, Apple is retrying

.inGracePeriod
Payment failed but access continues during grace period

.revoked
Apple 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

See references/app-review-guidelines.md for IAP rules (Guideline 3.1.1), subscription display requirements, and rejection prevention.

See references/storekit-advanced.md for subscription control styles, offer management, testing patterns, and advanced subscription handling.

For submission, privacy, metadata, screenshots, and rejection-risk audits use app-store-review.

For keyword, screenshot-caption, ranking, and conversion strategy use app-store-optimization.

Official Apple docs: Choosing a StoreKit API, Transaction.updates, Transaction.currentEntitlements,
SubscriptionStoreView, and PurchaseAction.