Modern IT platforms are forced to deliver content to a wide variety of client devices, including desktop browsers, mobile PWAs, tablets, and third-party smart devices. Under a classic microservices architecture, all these devices access a single universal backend API gateway. However, the needs of a mobile smartphone and a desktop PC differ dramatically: a mobile application requires a more compact data volume due to traffic limits, as well as a modified menu structure for a user-friendly UI. The solution to this technical problem was the implementation of the Backend For Frontend (BFF) pattern, a detailed analysis of which is available in the review at https://luckycaponecasino.org . The essence of the BFF concept is that instead of a single common API layer for all devices, isolated, lightweight backend layers are created for specific interface types. A single "BFF-Mobile" microservice is created, which handles requests exclusively from smartphones, and a separate "BFF-Web" service is created for desktop computers. These layers act as intelligent buffers between the client code and the platform's core internal services (authorization, payment, and catalog modules).