> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appcharge.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Initialize the Mobile Checkout SDK

After creating the configuration object, we can now initialize the checkout as follows:

```
CheckoutController.Instance.Init(callback);

CheckoutController.Instance.Init(customerId, callback);
```

| Argument     | Description                                              |
| ------------ | -------------------------------------------------------- |
| `callback`   | A callback interface implementation: `ICheckoutPurchase` |
| `customerId` | Customer Identification string                           |

The `ICheckoutPurchase` interface acts as a callback. The methods within the interface will be triggered based on the following events:

| Method                         | Description                                               | Arguments                                                                     |
| ------------------------------ | --------------------------------------------------------- | ----------------------------------------------------------------------------- |
| `OnInitialized`                | Triggered when the checkout initialization is completed.  |                                                                               |
| `OnInitializeFailed`           | Triggered when initialization has failed.                 | `ErrorMessage` containing a code and reason for the failure.                  |
| `OnPurchaseSuccess`            | Triggered when the purchase is completed successfully.    | `OrderResponseModel` containing detailed properties for the order.            |
| `OnPurchaseFailed`             | Triggered when the purchase fails for any reason.         | `ErrorMessage` containing a code and reason for the failure.                  |
| `OnPurchaseConsumed`           | Triggered when the purchase is consumed by the client.    | `true` if the purchase is consumed successfully, or `false` otherwise.        |
| `OnPricePointsSuccess`         | Triggered when price points are successfully retrieved.   | `PricePointsModel` containing details about the price points.                 |
| `OnPricePointsFail`            | Triggered when price points are not retrieved properly.   | `ErrorMessage` containing a code and reason for the failure.                  |
| `OnGetNonConsumeOrdersSuccess` | Triggered when none-consumed operation was success.       | Message will contain a List of order IDs that are waiting for being consumed. |
| `OnGetNonConsumeOrdersFail`    | Triggered when none-consumed operation failed to execute. | `ErrorMessage` containing a code and reason for the failure.                  |