Basis to use the services of DeuCS are the interfaces to transfer data. Merchants can choose between two types of interfaces: data gateways and  graphical user interfaces (GUIs).

Data gateways are highly flexible and can be integrated in nearly every shop solution. Merchants can choose between XML (Extensible Markup Language), SSL (Secure Socket Layer) and GICC (German ISO 8583 Credit Card-Protocol) Gateways.

Graphical user interfaces are less flexible than data gateways, but very easy to implement. Merchants only need to integrate a payment page module into their shop’s payment page. However, the main advantage of the GUIs offered by DeuCS is something else: The Payment Card Industry Data Security Standard (PCI DSS) is applicable to all parties which process or store card data. By using the graphical user interfaces of DeuCS merchants do not have to undergo a complex and expensive PCI certification. The data filled in to the GUI by the consumers is directly stored in the systems of DeuCS. As the merchant never has contact with the sensitive card data a PCI certification is unnecessary. Merchants can choose between Multi Pay GUI and [Smart Pay GUI], the latter offers a broad range of special benefits.