Django Apps Explained

Project vs App

A Django *project* is the top-level configuration for your entire website — settings, root URLs, WSGI/ASGI entry points. An *app* is a smaller Python package that implements one piece of functionality, such as a blog or a shopping cart. One project can (and usually does) contain many apps.

Note: A good rule of thumb: if a feature could be reused in a completely different website, it probably deserves its own app.

Example: Project vs App

startproject creates the project (the whole site's config); startapp creates blog/ as one self-contained piece of functionality inside it — that's the literal command-level difference between a project and an app.

django-admin startproject mysite
cd mysite
python manage.py startapp blog

What Lives Inside an App

Every Django app is a normal Python package (a folder with an __init__.py) that conventionally contains models.py for database tables, views.py for request-handling logic, urls.py for its own routes, and an admin.py for admin registration.

Example: What Lives Inside an App

Every app groups its own models.py (data) and views.py (request-handling) together — this Post model and post_list view both live inside the same blog/ app folder.

# blog/models.py
from django.db import models

class Post(models.Model):
    title = models.CharField(max_length=200)

# blog/views.py
from django.shortcuts import render
from .models import Post

def post_list(request):
    return render(request, 'blog/post_list.html', {'posts': Post.objects.all()})

Apps Are Reusable

Because an app only knows about its own models, views, and templates, the same app can be dropped into a different Django project with minimal changes. This is why many third-party Django packages (django-allauth, django-rest-framework) ship as installable apps.

Example: Apps Are Reusable

Because an app only knows about its own models, views, and templates, the same app can be dropped into a different Django project with minimal changes. This is why many third-party Django packages (django-allauth, django-rest-framework) ship as installable apps.

pip install django-allauth
# django-allauth is itself a Django app you add to INSTALLED_APPS