Is your job only limited to designing and developing mobile apps? No. Do you know, there is a difference between simply making apps and being a professional mobile application developer. In order to be a professional freelance mobile app developer , you will need to step up your game and adopt professional best practices, starting with proper mobile app design contracts. A written contract protects you and the people you work with. A well-drafted contract can make sure you get paid for your work and save you from painful and expensive legal headaches.