The Cardknox solution for Browser-Based POS systems (BBPOS) is a tray application that runs in the background on your computer. It acts as a local server allowing a POS application running in a browser to accept chip-based EMV (Europay, MasterCard, Visa) payments while remaining out of PCI scope. Our BBPOS solution supports all major terminals including PAX, Verifone, and Ingenico among others.


Complete the following steps to configure the BBPOS application.

  1. Download and install Cardknox BBPOS (PaymentEngineExt). Click here to download the file.
  2. Follow the prompts and enter the correct information. If you are unsure about a certain setting, leave the default setting as is. You can modify all settings by right clicking on Payment Engine in the system tray and choose options.
  3. Confirm that BBPOS is running in the background by its icon in the system tray.

Transaction Flow

  1. The POS sends an HTTP POST request containing transaction information, such as the transaction amount, to the local host
    Note: Transaction details should be in URL encoded Key-Value Pairs (KVP).
  2. Our BBPOS application receives the request and communicates with either the terminal or a pop-up window on the screen.
  3. The customer inserts their credit card into the terminal or keys the card number into the pop-up window.
  4. The transaction data is transmitted to the Cardknox gateway for authorization.
  5. When the transaction is complete, our BBPOS application sends back the transaction authorization details to your browser in the HTTP response through a redirect URL or AJAX. Transaction results are returned in the HTTP response in KVP format unless otherwise using xResponseFormat. See the Transaction Settings Table for more information.
  6. To cancel a currently processing transaction, send xCancel=1 to host
  7. You can find available and required commands and parameters at See the Custom Device Commands Table for BBPOS specific commands.
  8. The transaction can be redirected to a URL specified in xRedirectURL. See the Transaction Settings Table for more information.
  9. Go to for a sample implementation using a redirect.
  10. Go to for a sample implementation using AJAX.

Transaction Settings

You can configure transaction setting in the application setting file (right click on Payment Engine in the system tray and choose options) or in a transaction request. In the case of a conflict, settings set in the transaction request will override a setting set in the setting file. Use 1 and 0 for Boolean variables.

Settings File Name Transaction Request Name Parameter Description
xKey xKey Cardknox API Key
DeviceName xDeviceName Name of Device
DeviceCOMPort xDeviceComPort USB COM port assigned to device
DeviceBaud xDeviceComBaud Device Baud Rate
DeviceParity xDeviceComParity Device Parity
DeviceDataBits xDeviceComDataBits Device Data Bit
DeviceIP xDeviceIPPort IP Address assigned to device
DevicePort xDeviceIPAddress IP Port assigned to device
Device_Timeout xDeviceTimeOut Sets amount of time to wait from transaction
RequireAVS xRequireAVS Forces user to enter cardholder to enter AVS info for keyed transactions (Windows Only)
RequireCVV xRequireCVV Forces user to enter cardholder to enter card CVV for keyed transactions (Windows Only)
EnableDeviceInsertSwipeTap xEnableDeviceSwipe Enables device transactions
RequirePin xRequirePin Requires a PIN for Debit enabled cards
RequireSignature xRequireSignature Requires a signature
EnableWelcomeScreen xEnableWelcomeScreen If set to false, will disable device Welcome Screen
PrinterName N/A Sets printer to which receipts will be sent
ExitFormIfApproved xExitFormIfApproved Exits payment form after transaction approval without user interaction (Windows Only)
ExitFormIfNotApproved xExitFormIfNotApproved Exits payment form after transaction decline without user interaction (Windows Only)
ExitFormOnDeviceError xExitFormOnDeviceError Exits payment form after transaction error without user interaction (Windows Only)
EnableSilentMode xEnableSilentMode Payment form will not appear. Transaction will be handled solely on device
EnableKeyedEntry xEnableKeyedEntry Disables keyed transaction on payment form but does show form. Transaction will be handled solely on device.
EnableAmountConfirmationPrompt xEnableAmountConfirmationPrompt The device will prompt for a confirmation with the amount
N/A xResponseFormat Specifies Response format. Available formats are KVP, JSON, XML
N/A xRedirectURL Species a URL to which user will redirected to upon transaction completion

Custom Device Commands

These commands can be used to transport custom data to or from the device. They should be sent in the xCommand variable. These are standalone commands and are not used during a transaction. Appropriate device variables (xDeviceName, xIP etc) must be sent in. For commands that expect a payload, send in the payload as an xDeviceData variable.

Command Name Description
Device_ShowWelcomeScreen Displays Welcome Screen on the device
Device_SendData Sends data to device. Does not expect a response
Device_GetData Requests data from device
Device_GetFormEvent Requests form data from the device
Device_GetSignature Displays signature prompt on device. Returns Base64 encoded string. xDeviceData can be used to specify a location where signature will be stored as PNG file. xSignatureMessage can be used to display a signature message.
Device_ShowItems Show the items during a transaction.
Required fields xSerializationType=JSON, xAmount and xData with items in JSON format. Ex [{'xdescription':'Apples','xqty':1,'xunitprice':'.40'}, {'xdescription':'Oranges','xqty':2,'xunitprice':'.50'}]


BBPOS test sites

(Note: in order to use the test site you will need to have downloaded and run our application.)

Offline Transactions

Use the following integration when you are offline or cannot reach Cardknox

  1. Send the following command to BBPOS ( to initiate an offline transaction on the device xCommand=cc:encrypt
  2. Complete the transaction on the device or on the Payment Engine form
  3. If successful, you should receive a response as follows:

    "xCardNum": "4444330000001111;enc_1_1_Yu2tZUHL2ucliZwKaq5NMKBY5QDArSh8BcroZg4qT6sc39O8fLgRlBxVMQH1jpv+42s9IFTu2cSEi73j6qgtaLkQ5O8gZ2sPBgWnWjDjg6hvYeDJBBTjKh/ms6h6hAhgrfMD+3+ibgrt7OT2Ks2KHQ==_TThACh9hOhTiKte+qU9jRke7f08aAnrsNqjuToWyuP2onSh/ksQN5JOn3yWF2ECMIIrM/uT1MeC3HZxojDV+XDa7+4qJiuKgRh2yyNyAooBtyAh63IzhYd7gaIosEb2U7laOO5d6Zt2HJ4+br7P9hHIEbvElYH2O7uIaQN004c1pki1cJcs0n1ugPLvPpFwUMaUOYUi7z0RuEwX+n/bc9bLHyvYQAt1vo+Z0xteVifT/B0PrNLmGbpElRnwRNpf4koSV05HH363NH/Y4Yu2rnZnCjtOzn1NCPWkt41fUqiVTF1f9ZWCvU7iWR2cLd61Q7OwuT2VLP/c0WnMRbPXDEg==?", "xResult": "S", "xStatus": "Success", "xCommand": "cc:encrypt", "xAuthAmount": "1.99", "xSignatureRequired": "True", "xTransactionMode": "Unknown Entry Mode", "CVM": "Signature" }
  4. Store the xCardnum data locally until you have a connection and then submit the data as xCardnum or xMagStripe