> ## 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.

# Launch Checkout

### Setup the Product

In this step, create the product and set up its name, price, and additional information:

<CodeGroup>
  ```csharp csharp theme={"system"}
  var model = SessionRequestModel(  
      "John Doe",
      "[email protected]",
      129,
      "usd",
      "BestDealPackage",
      "Best_deal_package",
      "",
      "Coin Pack Bundle"  
  )  
  ```
</CodeGroup>

### Session Request Model Arguments

| Argument           | Is Mandatory | Description                                                                                            |
| ------------------ | ------------ | ------------------------------------------------------------------------------------------------------ |
| `customerId`       | `mandatory`  | The name or identifier of the customer.                                                                |
| `email`            |              | The customer's email address. Although not mandatory, providing it helps expedite the payment process. |
| `price`            | `mandatory`  | The price in `cents`, which will be converted by `Appcharge`.                                          |
| `currency`         | `mandatory`  | The currency used for the transaction, e.g., `usd`, `eur`.                                             |
| `offerName`        | `mandatory`  | The name of the offer.                                                                                 |
| `offerSku`         | `mandatory`  | The SKU number or text for the offer.                                                                  |
| `offerAssetUrl`    |              | A URL displaying an image for the offer.                                                               |
| `offerDescription` | `mandatory`  | A description of the offer.                                                                            |

### Session Metadata (Optional)

The session metadata allows you to add extra data for BI (Business Intelligence) and tracking purposes.

<CodeGroup>
  ```Text Kotlin theme={"system"}
  model.sessionMetadata.Add(key: String, value: String)
  ```
</CodeGroup>

### Adding Items to the Offer

You must add at least one item to the offer.

<CodeGroup>
  ```csharp csharp theme={"system"}
  var model = SessionRequestModel(...) // Your session model

  model.items.Add(new OfferItemModel(
  	"Coins",
  	"https://media-dev.appcharge.com/media/product-3.png",
  	"coins_xo",
  	300
  ));
  ```
</CodeGroup>

### Offer Item Arguments

| Argument          | Is Mandatory | Description                                                                                                                     |
| ----------------- | ------------ | ------------------------------------------------------------------------------------------------------------------------------- |
| `name`            | `mandatory`  | The name for the item                                                                                                           |
| `assetUrl`        | `mandatory`  | The URL of an image to display the item.                                                                                        |
| `sku`             | `mandatory`  | The SKU of the item.                                                                                                            |
| `quantity`        | `mandatory`  | The quantity of the item. For example, if the `name` is "Coins" and the `quantity` is 300, it will be displayed as "300 Coins." |
| `quantityDisplay` |              | The `Quantity Display` allows you to replace the numerical quantity with custom text.                                           |

### Open Checkout

In the final step, open the checkout by passing the product model to it:

<CodeGroup>
  ```csharp csharp theme={"system"}
  CheckoutController.Instance.OpenCheckout(model);
  ```
</CodeGroup>

At runtime, a new window will open, guiding the user through the purchase process. Based on user interaction, the following interface methods will be triggered:

| Method              | Description                                                                                       |
| ------------------- | ------------------------------------------------------------------------------------------------- |
| `OnPurchaseSuccess` | Triggered when the user successfully completes the purchase.                                      |
| `OnPurchaseFailed`  | Triggered when the checkout window is closed or if an error occurs during the purchasing process. |