# inAppPurchase > In-app purchases on Mac App Store. Process: [Main](../glossary.md#main-process) ## Events The `inAppPurchase` module emits the following events: ### Event: 'transactions-updated' Emitted when one or more transactions have been updated. Returns: * `event` Event * `transactions` ([Transaction[]](structures/transaction.md) - Array of transactions. ## Methods The `inAppPurchase` module has the following methods: ### `inAppPurchase.purchaseProduct(productID, quantity, callback)` * `productID` String - The id of the product to purchase. (the id of `com.example.app.product1` is `product1`). * `quantity` Integer (optional) - The number of items the user wants to purchase. * `callback` Function (optional) - The callback called when the payment is added to the PaymentQueue. (You should add a listener with `inAppPurchase.addTransactionsListener` to get the transaction status). * `isProductValid` Boolean - Determine if the product is valid and added to the payment queue. ### `inAppPurchase.canMakePayments()` Returns `true` if the user can make a payment and `false` otherwise. ### `inAppPurchase.getReceiptURL()` Returns `String`, the path to the receipt.