# 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[] - Array of [`Transaction`](structures/transaction.md) objects. ## Methods The `inAppPurchase` module has the following methods: ### `inAppPurchase.purchaseProduct(productID, quantity, callback)` * `productID` String - The identifiers of the product to purchase. (The identifier 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. * `isProductValid` Boolean - Determine if the product is valid and added to the payment queue. You should listen for the `transactions-updated` event as soon as possible and certainly before you call `purchaseProduct`. ### `inAppPurchase.getProducts(productIDs, callback)` * `productIDs` String[] - The identifiers of the products to get. * `callback` Function - The callback called with the products or an empty array if the products don't exist. * `products` Product[] - Array of [`Product`](structures/product.md) objects Retrieves the product descriptions. ### `inAppPurchase.canMakePayments()` Returns `Boolean`, whether a user can make a payment. ### `inAppPurchase.getReceiptURL()` Returns `String`, the path to the receipt. ### `inAppPurchase.finishAllTransactions()` Completes all pending transactions. ### `inAppPurchase.finishTransactionByDate(date)` * `date` String - The ISO formatted date of the transaction to finish. Completes the pending transactions corresponding to the date.