In order to use 'Wallet as a Service' there are no specific requirements. The product usually works seamlessly with any kind of program (such as App, Website, Software).
Please bear in mind that it is highly recommended to only run it from backend server. The server should communicate via API with the 'Wallet as a Service' and also communicates with the front-end system. Avoid any kind of client-side integration of the product for safety reasons.
A stable internet connection is recommended.