Cloud Payments require a basic integration of its payment gateway to be developed for DemandWare.
This integration should add a credit card payment method that submits the payments to the Cloud Payments RESTful JSON API. ... Functionality should also be added for Refunding through the DemandWare shopfront backend.
One of the deliverable items is documentation relating to setting up and installing the cartridge for developers and storefront owners.
... Documentation for the Cloud Payments API can be found at https://docs.pmnts.io/display/CPDOCS
Prior experience with developing DemandWare cartridges is required.