Developers are responsible for the coding, functionality, and architecture of an app. They work with graphic designers to create a user interface and with project managers to ensure that the app is completed on time and within budget. Builders are responsible for physically creating the app. They work with developers to turn their designs into a reality and with QA testers to ensure that the app functions properly.

The role of a developer is to design, build, and maintain software. The role of a builder is to design, build, and maintain software and systems. In order to be successful in either role, one must have strong technical skills and be able to think critically. Furthermore, it's important to be able to work well with others and have excellent communication skills. The best developers and builders are those who are always learning and keeping up with the latest trends in their field.