A method and system for enabling use of a reusable-code section across applications of different operating systems. For a first application designed for a first operating system (“OS”), a first native-code section and a reusable-code section are defined as part of the first application. For a second application designed for a second OS, a second native-code section and the reusable-code section are defined as part of the second application, and the second application is incapable of running on the first OS. The first and second native-code sections communicate with a web-services server, which communicates with a plurality of backend-services servers, at least some of which are controlled by different entities. The web-services server coordinates the execution of service requests with the backend-services servers on behalf of the first and second applications. The reusable-code section facilitates the display of user-interface elements when the first and second applications are executed.