Technical information for ePDQ Cardholder Payment Interface (CPI)

What you need to integrate ePDQ CPI

This end-to-end payment solution is securely hosted on our Barclaycard server.

Once your customer is ready to pay, they're redirected from your website to the ePDQ CPI page and we take full responsibility for processing the transaction. Once it's complete, we redirect the customer back to your site, and provide you with the transaction status details so you can fulfil the order.

Should you encounter any difficulties with integration, just give our dedicated technical support team a call.

Technical requirements

You should have a storefront, shopping basket or simple checkout page that:

• supports HTML 'POST' command
• can accept returned CGI data

In order to integrate ePDQ CPI, you need

• HTML and some scripts, as ePDQ CPI uses standard form Post to transmit data
• the use of server side scripting to perform encryption of transaction details
• a hosting company that supports server side scripting – we supply sample code in ASP, PHP, .NET and Perl.
• to configure Basic Authentication on the server to receive data back from ePDQ once a transaction is complete

ePDQ CPI processes the transaction details that your customers key in. To enable your website to present the screens to your customer you need to pass some basic information about the transaction to the ePDQ CPI. This includes:

• type of transaction (authorisation only or authorisation and capture)
• currency
• return URL – so that ePDQ can return your customer to your site
• transaction total
• your website/trading name
• unique information which we will provide for you

You may also submit:

• a unique order ID generated by your storefront to aid reconciliation
• the customer's address, if you'd like this to appear automatically when they enter their details on the payment page, for a smoother buying experience

Browsers that are compatible

ePDQ CPI has been fully tested with the following browsers:

• Microsoft Internet Explorer
• Firefox
• Safari
• Opera
• Google Chrome

In order to review transactions online using our management information, you need to access our Store Administration tool, which supports these browsers:

• Microsoft Internet Explorer
• Firefox
• Safari
• Opera
• Google Chrome

Please note: All browsers should be configured to accept cookies and JavaScript must be enabled.

Skills needed to integrate ePDQ CPI successfully

In order to integrate and start processing online transactions, you'll need someone with experience in commercial web development, including:

• HTML
• Client-side scripting
• Server-side scripting
• Order fulfilment and database design or management

An Example of how CPI works

Encryption

Step 1

Your customer browses your website, fills their shopping basket and clicks to go to the checkout. The CPI process starts here. A script on your website makes the first call to the encryption server, requesting the encryption of the transaction details. The transaction details include the total price to pay and the order details. Please note: If invalid data is provided the transaction will not process correctly.

Step 2

The encryption tool encrypts the transaction data. This generates an HTML <INPUT> tag containing the encrypted transaction data referred to as epdqdata string.
Please note, this HTML needs to be "pulled" back from the epdq server; it will not be posted to you.

Send data

Step 3

Your script then generates an HTML form. This must include the returned epdqdata string as a variable and the remaining mandatory variables. In addition you may include in the form any extended variables you wish to use. This form is submitted to the CPI payment page. Any extended variables that are included in the form pre-populate the payment page. This avoids the cardholder inputting the data twice, once on your website and once on the payment page.

Receive data

Step 4

Our customer completes the remaining fields on the CPI payment page, including their credit card number. Once the customer chooses to process with the transaction it is submitted for processing. The customer will be asked to Authenticate at this stage if appropriate.

Once the transaction is processed, the transaction status response and other details of the transaction are posted back to your pre-determined URL. This data allows you to fulfil the transaction and update the outcome of the transaction on your system.

Step 5

The CPI generates a response page which tells the cardholder what the outcome of the transaction was – approved or declined. If the response is a decline there may be a reason displayed to the cardholder. This page has a Continue button which once clicked, redirects the customer back to your website.

The Order ID is also sent across to your website so that you can identify the customer and link the customer to the detailed information sent in Step 4.