In Django, the architectural structure is divided into two distinct concepts: the Project and the App. Understanding the boundary between these two is fundamental to writing maintainable, idiomatic Django code.
The core tension is between Global Configuration and Specific Feature Logic. A project is a singular, overarching entity that configures an environment, whereas an app is a modular, reusable component that actually does the work.
You only ever create one Project per website or backend service. It is the container. You interact with project-level files when configuring databases, installing third-party packages, or defining the root URL tree.
You create an App every time you introduce a distinct domain of logic to your system. For example, if you add a blogging feature, you create a blog app. If you add a user payment system, you create a payments app.
Django Apps are designed to be plug-and-play. Theoretically, a well-written Django App (like a blogging app) could be taken from your current Django Project and dropped into a completely different Django Project, and it would work with minimal configuration. The Project’s job is simply to wire these independent apps together.