One-step purchase

Overview

When performing an one-time one-step purchase, you can use one of the following options to transfer payment details:

  • Transfer of complete payment details This is a basic option in which you collect all payment details from the customer, and then submit the data inside a payment request.
  • Transfer of payment details identifier To enable this option, you need to perform an initial COF payment. Once you do this, the payment platform creates a payment instrument record and returns a callback with the ID of the record in the account_id or card_id parameter. You need to specify this ID each time you submit to the payment platform a request for payment using stored credentials, see Saving payment data
  • Transfer of payment token To enable this option, you need to perform an initial payment. Once you do this, the payment platform creates a payment token and returns a callback with the token in the token parameter. You need to specify this ID each time you submit to the payment platform a request for payment using stored credentials. For more information about using tokens, see Tokens.

Workflow

When ordinary processing a one-step purchase by using Gate, the merchant web service is required to do the following:

  1. Send the one-step purchase request with payment details to one of the relevant endpoints in the following group: /v2/payment/{payment method}/sale[/specifying payment details].
  2. If necessary, complete the additional procedures:
    • 3‑D Secure 1 authentication. This authentication is intended to provide security to online payments by payment cards. For more information on the authentication workflow, as well as request and callback formats, see Customer authentication by using the 3‑D Secure 1.
    • Customer authentication on merchant's request. This authentication is intended to make purchases with payment cards more secure. For more information on the authentication workflow, as well as request and callback formats, see Authentication on merchant's request.
    • Additional payment information submission. This procedure is intended for cases in which the initial request did not contain the information needed by one of the payment process stakeholders (including authenticating customers). For more information on this procedure, see Submission of additional payment information.
  3. Receive a callback with the payment result from the payment platform.
  4. If needed, after completing a one-time one-step purchase you can return your customers their money, if the payment method supports refunds. For more information on this procedure, see Purchase refund.

The following diagram provides the detailed picture of an ordinary one-step purchase processing procedure without additional requests.

Figure 1. Processing of a one-step purchase
  1. Customer initiates a purchase on the merchant web service.
  2. The web service sends the request for processing a one-step purchase by using Gate to the specified maxaa URL.
  3. The payment platform receives the request for processing a one-step purchase by using Gate.
  4. The payment platform performs the request acceptance that includes validation of the required parameters and signature.
  5. The payment platform sends to the web service response with request receipt confirmation and correctness check result.
  6. The payment platform performs the internal request processing and sends it to the card organisation.
  7. The card organisation performs the internal request processing and sends it to the issuer.
  8. The issuer performs the internal request processing and debiting customer account.
  9. The issuer sends the callback with a one-step purchase result to the card organisation.
  10. The card organisation sends the callback with a one-step purchase result to the maxaa payment platform.
  11. The payment platform sends the callback to the web service.
  12. The customer receives the payment result from the web service.

The sections that follow discuss in more details the request format and the required parameters and the information about the format of callbacks with payment results. For the general information on how to use the API, see Integration procedure.