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

# Create Exchange from Payment Link

> How to calculate a rate and create an exchange order from a payment link

When a payer opens a payment link, they need to calculate how much they will send in their own currency, then create an exchange. This is a two-step process: fetch the rate first, then create the exchange.

***

## Step 1: Fetch the Payment Link Rate

**Endpoint:** `GET /utility/payment-link-rate`

This endpoint calculates the equivalent amount in the payer's currency for a given payment link. The `amount` parameter should be set to the payment link's original amount.

* `toCurrency` and `toCurrencyIso2` represent the currency and ISO2 code of the payment link (the receiver's currency).
* `fromCurrency` and `fromCurrencyIso2` represent the payer's currency and ISO2 code.

**Example:** A payment link is created for `200 GHS` by a receiver in Ghana. The payer is in Nigeria using `NGN`. The request parameters would be:

| Parameter          | Value |
| ------------------ | ----- |
| `fromCurrency`     | `NGN` |
| `fromCurrencyIso2` | `NG`  |
| `toCurrency`       | `GHS` |
| `toCurrencyIso2`   | `GH`  |
| `amount`           | `200` |

### Response

```json theme={null}
{
  "success": true,
  "data": {
    "displayAmount": "123.84",
    "orderAmount": 123.83216789,
    "offerId": "67d830049d46873b7891dd0f"
  },
  "message": "payment link rate fetched successfully"
}
```

| Field           | Description                                                                          |
| --------------- | ------------------------------------------------------------------------------------ |
| `displayAmount` | Formatted amount for UI display only. Do not use this for the exchange request.      |
| `orderAmount`   | The exact amount to pass as `amount` when creating the exchange. Use the full value. |
| `offerId`       | Required when creating the exchange. Pass this as the `offerId` path parameter.      |

***

## Step 2: Create the Exchange

**Endpoint:** `POST /offer/{offerId}/payment-request/order`

Use the `offerId` from the rate response as the path parameter and the full `orderAmount` as the `amount` field in the request body.

The `buyerCreditPaymentDetails` should be automatically mapped from the receiver's payout configuration returned when the payment link was retrieved via `/payment-link/pay` — including `currency`, `currencyIso2`, and payment details. This ensures the receiver's payout method stays consistent with the original payment link setup.

The `buyerDebitPaymentDetails` must be provided by the payer and should include all required fields for their chosen payment method.

Refer to the [Supported Payment Methods](/guides/supported-payment-methods) guide for the required fields per payment method.

### Request Body

```json theme={null}
{
  "amount": 123.83216789,
  "buyerDebitPaymentMethod": "MOBILE_MONEY",
  "buyerCreditPaymentMethod": "BANK_TRANSFER",
  "buyerCreditPaymentDetails": {
    "accountName": "MONIRATES LIMITED",
    "accountNumber": "0115847370",
    "providerName": "SAFE HAVEN SANDBOX BANK",
    "paymentMethod": "BANK_TRANSFER",
    "iso2": "NG",
    "currency": "NGN",
    "bankCode": "999240"
  },
  "buyerDebitPaymentDetails": {
    "accountName": "MONIRATES LIMITED",
    "accountNumber": "0115847370",
    "providerName": "MTN",
    "paymentMethod": "MOBILE_MONEY",
    "iso2": "GH",
    "currency": "GHS",
    "network": "MTN"
  }
}
```

### Fields

| Field                       | Required | Description                                                                            |
| --------------------------- | -------- | -------------------------------------------------------------------------------------- |
| `amount`                    | Yes      | The full `orderAmount` from the rate response.                                         |
| `buyerDebitPaymentMethod`   | Yes      | How the payer will send funds.                                                         |
| `buyerCreditPaymentMethod`  | Yes      | How the receiver will receive funds.                                                   |
| `buyerDebitPaymentDetails`  | Yes      | Payment details for the payer. Must match the selected debit payment method.           |
| `buyerCreditPaymentDetails` | Yes      | Payment details for the receiver. Mapped from the payment link's payout configuration. |

***

## Step 3: Confirm Payment

Once the exchange is successfully created, call the buyer paid endpoint to notify the system that payment has been made.

**Endpoint:** `POST /order/{orderId}/payment-request/buyer-paid`

The `orderId` is the `_id` from the exchange creation response. See the [Payment Made](/guides/payment-made) guide for how to structure the request body based on the debit payment method used.