> ## 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 WebGL SDK

Initialize the SDK using the following function:

<CodeGroup>
  ```Text C# theme={"system"}
  CheckoutController.Instance.Init(string CustomerId, string GAID, ICheckoutPurchase callback);
  ```
</CodeGroup>

| Argument     | Type                | Description            |
| ------------ | ------------------- | ---------------------- |
| `customerId` | `string`            | Customer ID.           |
| `GAID`       | `string`            | Google Advertising ID. |
| `callback`   | `ICheckoutPurchase` | Interface callback.    |

> **Important:** This function must be called during the game's boot process.

If the request is successful, the `OnInitialize` callback is triggered, indicating that the initialization was completed. If the request fails, the `OnInitializeFailed` callback is triggered with an error code. Follow the instructions in the [WebGL SDK troubleshooting](./troubleshooting) article and try to re-initialize again based on the error.

For more details on the callbacks you need to implement and how to handle them, refer to the [Implement the WebGL SDK Callbacks](./implement-the-callbacks) article.