SKILL.md
iOS StoreKit
Expert guidance for implementing in-app purchases with StoreKit 2.
Setup
Configure Products in App Store Connect
- Create app in App Store Connect
- Add in-app purchases (Subscriptions, Consumables, Non-Consumables)
- Configure pricing and availability
StoreKit Configuration (Testing)
Create Configuration.storekit file for local testing.
Store Manager
import StoreKit
@MainActor
class StoreManager: ObservableObject {
@Published var products: [Product] = []
@Published var purchasedProductIDs: Set<String> = []
@Published var isLoading = false
private let productIDs: Set<String> = [
"com.app.premium.monthly",
"com.app.premium.yearly",
"com.app.coins.100",
"com.app.removeads"
]
private var updateListenerTask: Task<Void, Error>?
init() {
updateListenerTask = listenForTransactions()
Task {
await loadProducts()
await updatePurchasedProducts()
}
}
deinit {
updateListenerTask?.cancel()
}
}Loading Products
Fetch Products
func loadProducts() async {
isLoading = true
defer { isLoading = false }
do {
products = try await Product.products(for: productIDs)
.sorted { $0.price < $1.price }
} catch {
print("Failed to load products: \(error)")
}
}Product Types
extension Product {
var isSubscription: Bool {
type == .autoRenewable
}
var isConsumable: Bool {
type == .consumable
}
var isNonConsumable: Bool {
type == .nonConsumable
}
}Purchases
Purchase Product
func purchase(_ product: Product) async throws -> Transaction? {
let result = try await product.purchase()
switch result {
case .success(let verification):
let transaction = try checkVerified(verification)
await updatePurchasedProducts()
await transaction.finish()
return transaction
case .userCancelled:
return nil
case .pending:
return nil
@unknown default:
return nil
}
}
private func checkVerified<T>(_ result: VerificationResult<T>) throws -> T {
switch result {
case .unverified:
throw StoreError.verificationFailed
case .verified(let safe):
return safe
}
}Transaction Listener
func listenForTransactions() -> Task<Void, Error> {
Task.detached {
for await result in Transaction.updates {
do {
let transaction = try await self.checkVerified(result)
await self.updatePurchasedProducts()
await transaction.finish()
} catch {
print("Transaction failed verification: \(error)")
}
}
}
}Subscriptions
Check Subscription Status
func updatePurchasedProducts() async {
var purchased: Set<String> = []
for await result in Transaction.currentEntitlements {
do {
let transaction = try checkVerified(result)
if transaction.revocationDate == nil {
purchased.insert(transaction.productID)
}
} catch {
print("Failed to verify transaction: \(error)")
}
}
await MainActor.run {
self.purchasedProductIDs = purchased
}
}Subscription Info
func getSubscriptionStatus(for groupID: String) async throws -> Product.SubscriptionInfo.Status? {
guard let product = products.first(where: { $0.subscription?.subscriptionGroupID == groupID }) else {
return nil
}
return try await product.subscription?.status.first
}
func isSubscriptionActive(groupID: String) async -> Bool {
do {
guard let status = try await getSubscriptionStatus(for: groupID) else {
return false
}
switch status.state {
case .subscribed, .inGracePeriod:
return true
default:
return false
}
} catch {
return false
}
}Subscription Period Display
extension Product.SubscriptionPeriod {
var displayName: String {
switch unit {
case .day:
return value == 7 ? "Weekly" : "\(value) Day\(value > 1 ? "s" : "")"
case .week:
return "\(value) Week\(value > 1 ? "s" : "")"
case .month:
return value == 1 ? "Monthly" : "\(value) Months"
case .year:
return value == 1 ? "Yearly" : "\(value) Years"
@unknown default:
return "Unknown"
}
}
}Restore Purchases
func restorePurchases() async throws {
try await AppStore.sync()
await updatePurchasedProducts()
}SwiftUI Views
Product List View
struct StoreView: View {
@StateObject private var store = StoreManager()
var body: some View {
List {
Section("Subscriptions") {
ForEach(store.products.filter { $0.isSubscription }) { product in
ProductRow(product: product, isPurchased: store.purchasedProductIDs.contains(product.id)) {
Task {
try await store.purchase(product)
}
}
}
}
Section("One-Time Purchases") {
ForEach(store.products.filter { !$0.isSubscription }) { product in
ProductRow(product: product, isPurchased: store.purchasedProductIDs.contains(product.id)) {
Task {
try await store.purchase(product)
}
}
}
}
Section {
Button("Restore Purchases") {
Task {
try await store.restorePurchases()
}
}
}
}
}
}
struct ProductRow: View {
let product: Product
let isPurchased: Bool
let action: () -> Void
var body: some View {
HStack {
VStack(alignment: .leading) {
Text(product.displayName)
.font(.headline)
Text(product.description)
.font(.caption)
.foregroundStyle(.secondary)
}
Spacer()
if isPurchased {
Image(systemName: "checkmark.circle.fill")
.foregroundStyle(.green)
} else {
Button(product.displayPrice, action: action)
.buttonStyle(.borderedProminent)
}
}
}
}Subscription Store View (iOS 17+)
import StoreKit
struct PremiumView: View {
var body: some View {
SubscriptionStoreView(groupID: "your_group_id") {
VStack {
Image(systemName: "star.fill")
.font(.largeTitle)
Text("Go Premium")
.font(.title)
}
}
.subscriptionStoreButtonLabel(.multiline)
.subscriptionStorePickerItemBackground(.ultraThinMaterial)
}
}Offer Codes & Promotions
Redeem Offer Code
func redeemOfferCode() async {
// Opens App Store offer code redemption sheet
try? await AppStore.presentOfferCodeRedeemSheet()
}Promotional Offers
func purchaseWithOffer(_ product: Product, offerID: String) async throws -> Transaction? {
guard let offer = product.subscription?.promotionalOffers.first(where: { $0.id == offerID }) else {
return nil
}
// Generate signature on your server
let signatureData = try await generateSignature(for: offer)
let result = try await product.purchase(options: [
.promotionalOffer(
offerID: offer.id,
keyID: signatureData.keyID,
nonce: signatureData.nonce,
signature: signatureData.signature,
timestamp: signatureData.timestamp
)
])
// Handle result...
}Receipt Validation
App Store Server API
// Server-side validation recommended
// Use App Store Server API for subscription status
func validateReceipt() async throws -> Bool {
guard let appStoreReceiptURL = Bundle.main.appStoreReceiptURL,
FileManager.default.fileExists(atPath: appStoreReceiptURL.path) else {
return false
}
let receiptData = try Data(contentsOf: appStoreReceiptURL)
let receiptString = receiptData.base64EncodedString()
// Send to your server for validation
return try await validateOnServer(receipt: receiptString)
}Error Handling
enum StoreError: LocalizedError {
case verificationFailed
case purchaseFailed
case productNotFound
var errorDescription: String? {
switch self {
case .verificationFailed: return "Transaction verification failed"
case .purchaseFailed: return "Purchase could not be completed"
case .productNotFound: return "Product not found"
}
}
}Testing
StoreKit Testing in Xcode
#if DEBUG
func clearPurchaseHistory() async {
// Only works in sandbox/testing
for await result in Transaction.currentEntitlements {
guard case .verified(let transaction) = result else { continue }
await transaction.finish()
}
}
#endif