Integration using Checkout Page

This form of integration allows you to get a head start on integration and saves you the trouble of building your own UI, generating user addresses for each currency and displaying them to the user.

The main mode of operation of XGateway is using invoices with a fixed exchange rate.

Please read this page before starting. The invoice creation API uses several parameters that need explanation.

Fixed Rate invoices

A fixed rate invoice locks exchange rate for the transfer of funds for 15 minutes. After this period the invoice is marked as expired.

In order to create a Fixed Rate invoice in the payment processing system, you need to make a POST request to the Invoice API v2 endpoint. To manage the display of currencies on checkout page — use displayCurrencies parameter. When an array is provided, the function preserves and respects the specified order of the currencies. If parameter is not provided — checkout will show every enabled currency

Note, that baseCurrency parameter defines the expected currency of the deposit. It does not change or affect the reference currency - the currency used for all the internal accounting for you as a merchant.

The request may specify application (applicationId). This is an optional parameter used to customise the look and feel of the checkout page. Every application contains its own settings set to tailor the checkout page for different needs.

The customer identificator is a mandatory field, which must contain the id of the customer, used in your system. This id is sent back in the callbacks on every deposit in order to link deposits with corresponding customers.

The order identificator is an optional parameter, which will be sent back to your system with a callback for the deposit linked to this exact invoice.

The payment currency and customer data are needed for peer-to-peer and bank transfer solutions if you want to speed up the checkout flow and provide customer details from your side. Otherwise, the customer will need to fill out the required forms manually.

Create an invoice for the customer for a specified currency and optional order id.

Creates an invoice using a fixed or floating exchange rate strategy. The invoice is generated based on the provided parameters, including amount, base currency, customer ID, and optionally, an order ID.

If paymentCurrency is provided and all required activation parameters for a specific provider are included (customerFirstName, customerLastName, customerEmail, customerCountry, customerPhone), the invoice is instantly activated.

Returns a checkout link upon successful creation.

Access to this endpoint requires a valid API key. The API key is sent in the x-api-key header on requests.

post

/invoices

Authorizations

Body

amountnumber · doublerequired

applicationIdstring

baseCurrencystring · enumrequired

Represents all currencies in the payment processing system.

Used to specify the currency of accounts, exchange rates, and transactions in the payment processing system.

It provides a controlled and standardized list of supported currencies for all transactions and balances in the payment processing system.

New currencies can be added to the payment processing system as additional members.

Options: BNB, bUSDT, BTC, ETH, eUSDC, eUSDT, FTN, POL, pUSDC, SOL, sUSDT, tUSDC, tUSDT, wpUSDC, wpUSDT, EUR, GBP, AZN, BDT, INR, JPY, PKR, RUB, TRY, UZS, AUD, BRL, CAD, CHF, CZK, DKK, KES, NOK, NZD, SEK, USD, USDC, USDT, TRX

customerCountrystring

customerEmailstring

customerFirstNamestring

customerIdstringrequired

customerLastNamestring

customerPhonestring

displayCurrenciesany of

Represents all currencies in the payment processing system.

Used to specify the currency of accounts, exchange rates, and transactions in the payment processing system.

It provides a controlled and standardized list of supported currencies for all transactions and balances in the payment processing system.

New currencies can be added to the payment processing system as additional members.

Represents all currencies in the payment processing system.

Used to specify the currency of accounts, exchange rates, and transactions in the payment processing system.

It provides a controlled and standardized list of supported currencies for all transactions and balances in the payment processing system.

New currencies can be added to the payment processing system as additional members.

invoiceStrategystring · enum

Represents the possible strategies of an invoice.

Options: floating, fixed

orderIdstring

paymentCurrencystring · enum

Represents all currencies in the payment processing system.

Used to specify the currency of accounts, exchange rates, and transactions in the payment processing system.

It provides a controlled and standardized list of supported currencies for all transactions and balances in the payment processing system.

New currencies can be added to the payment processing system as additional members.

Options: BNB, bUSDT, BTC, ETH, eUSDC, eUSDT, FTN, POL, pUSDC, SOL, sUSDT, tUSDC, tUSDT, wpUSDC, wpUSDT, EUR, GBP, AZN, BDT, INR, JPY, PKR, RUB, TRY, UZS, AUD, BRL, CAD, CHF, CZK, DKK, KES, NOK, NZD, SEK, USD, USDC, USDT, TRX

Responses

application/json

application/json

application/json

application/json

application/json

cURL

JavaScript

Python

HTTP

cURL

curl -L \
  --request POST \
  --url 'https://api.xgateway.tech/api/v2/invoices' \
  --header 'x-api-key: YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "amount": 1,
    "applicationId": "text",
    "baseCurrency": "BNB",
    "customerCountry": "text",
    "customerEmail": "text",
    "customerFirstName": "text",
    "customerId": "text",
    "customerLastName": "text",
    "customerPhone": "text",
    "displayCurrencies": "BNB",
    "invoiceStrategy": "floating",
    "orderId": "text",
    "paymentCurrency": "BNB"
  }'

201

400

401

422

500

201

{
  "data": "[checkout link]",
  "success": true
}

Created

Remember to authorise the request with your x-api-key header.

Headers

Name	Type	Description
x-api-key*	String	Your API key

Session Life

Invoices at the moment of creation have no expiration time. After invoice activation on the checkout page (when the customer selects the payment currency and clicks "Proceed"), the system will set an expiration time according to invoice TTL. Once an invoice has expired, the link will show an error.

You can make several requests for the same customer with a different amount/base currency and get a different checkout link back.

Invoice time to live(TTL)

The time to live for floating invoices is 24 hours.

The time to live for fixed invoices can be configured during merchant creation and can also be adjusted later in the Merchant's back office. The default value for the invoice TTL is 1200 seconds, which is equivalent to 20 minutes.

Pre-populate the form

The KYC flow through the Checkout V2 supports pre-population of fields in case your service already has the personal data of the customers. This function is only available for banking onramp. In order to pre-populate the form add the information into the URL parameters (query parameters) when working with an invoice. See the example below.

Query Params

Used to pre-fill customer data on the checkout page.

• firstName

• lastName

• email

• address1

• address2

• postCode

• city

• country: (ISO 3166-1 alfa-2 country code)

• dateOfBirth: YYYY-MM-DD

• sourceOfFunds: SALARY, BUSINESS_INCOME, PENSION, OTHER

Add all or some query params to a URL. Example of usage:

https://checkout.xgateway.dev/v2/invoice/4f61498c-6e80-4b15-a88a-b7e5a29292bd?firstName=Genry&lastName=Pollok&email=[e-mail]&address1=Some-Street 12 tn.2&address2=ap.3&postCode=12345&city=New York&country=US&dateOfBirth=1984-09-09&sourceOfFunds=SALARY