Need to build app for course selling

I am in need of a developer to build an app for me to sell academic courses. The app should be built for both iOS and Android platforms. The app should have a course catalog feature that allows users to easily browse and purchase courses. Payment integration should also be included to make transactions seamless. Additionally, it is important for the app to have user progress tracking functionality to help users keep track of their course progress. Ideal skills for this job include experience developing for both iOS and Android platforms, proficiency in payment integration, and knowledge of course catalog development.