💰 In-App Purchase (StoreKit)

Apple's payment system for digital goods: consumables (coins), non-consumables (lifetime unlock), auto-renewable subscriptions (live in Subscription Groups), and non-renewing subscriptions. Modern apps use StoreKit 2 (Product.products(for:), product.purchase(), Transaction.currentEntitlements) or a wrapper like RevenueCat. Apple takes 30% (15% with the Small Business Program or after year 1 of a subscription).

Mandatory for selling digital content or features consumed in the app (Guideline 3.1.1): premium tiers, coins, content unlocks. Forbidden for physical goods and real-world services — those must use Stripe/Apple Pay/etc. (Guideline 3.1.3(e), 3.1.5). US storefront link-out entitlements exist post-Epic v. Apple — check current policy before relying on external checkout.