Building a web application for a project is one. There is not a log a thing to consider when building this because it's just for fun and might only be used by a few people. Building an application for customers, people you haven't seen, and are going to use your service is a different thing. A lot of analysis, careful planning, structuring, and the organization has to go into this. If not, when the time comes to revisit, make changes, or scale it's just going to be nightmare. As a front engineer, I specialize in not making your web app a nightmare for you and your customers.