Axiom Storekit Ref

Non-Renewing Subscription:

• Fixed duration subscriptions (no auto-renewal)
• Examples: seasonal passes
• MUST restore on new devices

Key Improvements Over StoreKit 1

• Async/Await: Modern concurrency instead of delegates/closures
• Automatic Verification: JSON Web Signature (JWS) verification built-in
• Transaction Types: Strong Swift types instead of SKPaymentTransaction
• Testing: StoreKit configuration files for local testing
• SwiftUI Views: Pre-built purchase UIs (ProductView, SubscriptionStoreView)
• Server APIs: App Store Server API and Server Notifications

When to Use This Reference

Use this reference when:

• Implementing in-app purchases with StoreKit 2
• Understanding new iOS 18.4 fields (appTransactionID, offerPeriod, etc.)
• Looking up specific API signatures and parameters
• Planning subscription architecture
• Debugging transaction issues
• Implementing StoreKit Views
• Integrating with App Store Server APIs

Related Skills:

• axiom-in-app-purchases — Discipline skill with testing-first workflow, architecture patterns
• (Future: iap-auditor agent for auditing existing IAP code)
• (Future: iap-implementation agent for implementing IAP from scratch)

Product

Overview

Product represents an in-app purchase item configured in App Store Connect or StoreKit configuration file.

Loading Products

Basic Loading:

import StoreKit

let productIDs = [
    "com.app.coins_100",
    "com.app.premium",
    "com.app.pro_monthly"
]

let products = try await Product.products(for: productIDs)

From WWDC 2021-10114

Handling Missing Products:

let products = try await Product.products(for: productIDs)

// Check what loaded
let loadedIDs = Set(products.map { $0.id })
let missingIDs = Set(productIDs).subtracting(loadedIDs)

if !missingIDs.isEmpty {
    print("Missing products: \(missingIDs)")
    // Products not configured in App Store Connect or .storekit file
}

Product Properties

Basic Properties:

let product: Product

product.id // "com.app.premium"
product.displayName // "Premium Upgrade"
product.description // "Unlock all features"
product.displayPrice // "$4.99"
product.price // Decimal(4.99)
product.type // .nonConsumable

Product Type Enum:

switch product.type {
case .consumable:
    // Coins, hints, boosts
case .nonConsumable:
    // Premium features, level packs
case .autoRenewable:
    // Monthly/annual subscriptions
case .nonRenewing:
    // Seasonal passes
@unknown default:
    break
}

Subscription-Specific Properties

Check if Product is Subscription:

if let subscriptionInfo = product.subscription {
    // Product is auto-renewable subscription
    let groupID = subscriptionInfo.subscriptionGroupID
    let period = subscriptionInfo.subscriptionPeriod
}

Subscription Period:

let period = product.subscription?.subscriptionPeriod

switch period?.unit {
case .day:
    print("\(period?.value ?? 0) days")
case .week:
    print("\(period?.value ?? 0) weeks")
case .month:
    print("\(period?.value ?? 0) months")
case .year:
    print("\(period?.value ?? 0) years")