This is an introductory course, designed to help you becoming familiar with the core concepts of Codeless UI programming. You will learn how to use a visual client-server development platform to build mobile and web applications. The platform we will use is called Backendless. It is a complete (full-stack) system where you can design dynamic web/mobile applications using an intuitive graphical interface, add logic without any coding using our Codeless system and connect it with a powerful and highly scalable backend. This course focuses on the visual UI builder part of the system, however, we will also look into the client-server integration aspect of app development. The course is an introduction to the Backendless system. It is a pre-requisite for an in-depth, comprehensive course dedicated to Codeless development.