# Core Write Methods

#### createCryptoCheckout

Creates a new crypto checkout session. The SDK handles authentication and request signing internally. The returned object contains the session ID, payment address, and status needed to render a pay screen in your UI.

```
const checkout = await paymentClient.createCryptoCheckout({
  participantCode: "merchant-1",
  amountToPay: 100,
  currencyToPay: "USDT",
  clientReference: "order-1",
  paymentPurpose: {
    subject: "Order #1",
    description: "Premium subscription",
  },
  buyerInfo: {
    fullLegalName: "Alice Example",
  },
  expiry: Math.floor(Date.now() / 1000) + 15 * 60,
});
```

| Parameter         | Type     | Description                                                                     |
| ----------------- | -------- | ------------------------------------------------------------------------------- |
| `participantCode` | `string` | Merchant or participant identifier issued during onboarding.                    |
| `amountToPay`     | `number` | Settlement amount in the specified currency.                                    |
| `currencyToPay`   | `string` | Currency code for the checkout (e.g. `"USDT"`, `"USDC"`).                       |
| `clientReference` | `string` | Your own idempotent reference for the order. Used to fetch the checkout later.  |
| `paymentPurpose`  | `object` | Contains `subject` and `description` fields displayed to the buyer.             |
| `buyerInfo`       | `object` | Contains `fullLegalName` of the payer.                                          |
| `expiry`          | `number` | Unix timestamp (seconds) after which the checkout session is no longer payable. |


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