StoreKit 2 API Reference

Complete API reference for StoreKit 2 in-app purchases. Covers Product, Transaction, subscriptions, StoreKit Views, and App Store Server APIs.

When to Use This Reference

Use this reference when you need:

• Specific API signatures and parameters
• iOS 18.4 field additions (appTransactionID, offerPeriod, etc.)
• Transaction lifecycle and verification details
• Subscription status and renewal info structures
• StoreKit Views configuration options
• Server API endpoints and payloads

For implementation workflow: See in-app-purchases for testing-first patterns and architecture.

Example Prompts

Questions you can ask Claude that will draw from this reference:

• "What are all the fields on Transaction and what do they mean?"
• "How do I check if a subscription is in grace period?"
• "What's the difference between RenewalInfo and SubscriptionStatus?"
• "How do I customize ProductView appearance?"
• "What fields are new in iOS 18.4 for StoreKit?"
• "How do I verify a transaction on my server?"

What's Covered

Product API

• Product.products(for:) loading
• Product.PurchaseResult handling
• Product.SubscriptionInfo for subscription details
• Purchase options (quantity, promotionalOffer)

Transaction API

• Transaction structure and all fields
• Transaction.updates listener
• Transaction.currentEntitlements
• Transaction.finish() timing
• VerificationResult and JWS verification

Subscription APIs

• RenewalInfo for upcoming renewals
• SubscriptionStatus for current state
• Grace period detection
• Offer types (introductory, promotional, win-back)

StoreKit Views (iOS 17+)

• ProductView for single products
• SubscriptionStoreView for subscription groups
• Customization and styling options
• Integration with purchase flow

Product Types

• Consumable (coins, hints)
• Non-consumable (premium features)
• Auto-renewable subscriptions
• Non-renewing subscriptions

App Store Server APIs

• Server notifications (V2)
• Transaction history endpoint
• Subscription status endpoint
• Look up order ID

iOS 18.4 Enhancements

• appTransactionID field
• offerPeriod for subscription offers
• Enhanced renewal info

Key Pattern

Transaction Structure

// Key Transaction fields
struct Transaction {
    let id: UInt64                        // Unique transaction ID
    let productID: String                 // Product identifier
    let purchaseDate: Date                // When purchased
    let expirationDate: Date?             // For subscriptions
    let revocationDate: Date?             // If refunded
    let isUpgraded: Bool                  // If upgraded to higher tier
    let offerType: OfferType?             // Trial, intro, promo, win-back
    let appTransactionID: String?         // iOS 18.4+ app-level ID
}

// Verification
switch result {
case .verified(let transaction):
    // Safe to use
case .unverified(let transaction, let error):
    // Verification failed
}

Subscription Status Check

// Check subscription state
let statuses = try await Product.SubscriptionInfo.status(for: groupID)
for status in statuses {
    switch status.state {
    case .subscribed:
        // Active subscription
    case .expired:
        // Subscription ended
    case .inBillingRetryPeriod:
        // Payment failed, retrying
    case .inGracePeriod:
        // Payment failed, still granting access
    case .revoked:
        // Refunded
    }
}

Documentation Scope

This page documents the axiom-storekit-ref reference skill—complete API coverage Claude uses when you need specific StoreKit 2 API details.

For implementation patterns: See in-app-purchases for testing-first workflow and architecture patterns.

Related

• in-app-purchases — Implementation patterns and testing workflow
• iap-auditor — Automated IAP code scanning

Resources

WWDC: 2025-241, 2025-249, 2023-10013, 2021-10114

Docs: /storekit, /storekit/product, /storekit/transaction