Quick Guide For Developers

Quick Guide For Developers

For PHP we provide an example code on GitHub.

1. Invoking QPAY Checkout Page

Browser initiation (default usage)

To initiate the payment process with QENTA Checkout Page send a POST request to: https://api.qenta.com/page/init.php

The browser receives an HTTP response with the header Location and redirects to the Checkout Page.

Server-to-server initiation

Alternatively, the same request can be sent to https://api.qenta.com/page/init-server.php The response is in the following format:

If you use server-to-server initiation then parameters consumerIpAddress and consumerUserAgent are mandatory.

Both requests need to contain the required request parameters and should at least contain the highly recommended optional parameters.

In case an error is returned, refer to the error codes listing.

2. Handling The Response

When defining the request parameters, the URLs leading the consumer back to the shop need to be set.

Table 1. Relevant URLs
URL Description


Payment was successful


Payment process was canceled by the consumer


Payment failed, e.g. due to a wrong 3-D Secure Code


Payment is pending

We recommend defining the parameter confirmURL to get a server-to-server communication of the outcome, regardless if the customer is being redirected back to your shop or not.

To prevent fraud, check the authenticity of returned data for pending and successful payments by calculating the fingerprint. This is done by concatenating all response parameter values plus your secret in the order defined in the parameter responseFingerprintOrder without any dividers in between and using the secret as a cryptographic key for the hashing function. The resulting fingerprint has to be identical to the value of the response parameter responseFingerprint.

For a PHP example on how to calculate a fingerprint take a look at our reference implementation at the link QENTA Checkout Client Library.
Save all relevant data persistently.

You can submit the same URL for all four parameters and provide the appropriate content after interpreting the payment process results.

3. Backend Operations

Refer to technical implementation for integrating backend operations in general and to each available transaction-based operation.