myapp

myapp#

What is myapp?#

myapp is a Django application.

In Django:

  • A project = whole website (settings, config, deployment)

  • An app = one feature or module inside the project

Examples of apps:

  • Blog

  • Accounts

  • Products

  • Orders

  • Payments

Here myapp is a feature container, not the whole site.

How to Create an App in Django#

Step0: Make sure you are in the right place#

You must be inside the Django project directory, where manage.py exists.

Example:

mysite/
├── manage.py
├── mysite/

Check:

ls

You should see:

manage.py

Step1: Activate your virtual environment#

If you’re using venv:

macOS / Linux

source djenv/bin/activate

Windows

djenv\Scripts\activate

You should see something like:

(djenv)

Step2: Create the Django app#

A Django app is created using python manage.py startapp appname, then registered in INSTALLED_APPS to become active.

Run:

python manage.py startapp myapp
Replace myapp with your app name:

  • blog

  • accounts

  • products

  • orders

Step3: What Django creates for you#

After running the command, Django generates:

myapp/
├── migrations/
│   └── __init__.py
├── __init__.py
├── admin.py
├── apps.py
├── models.py
├── tests.py
├── views.py

This is a complete app skeleton.

Step4: Register the app#

Open:

mysite/settings.py

Find:

INSTALLED_APPS = [
   'django.contrib.admin',
   'django.contrib.auth',
   ...
]

Add your app:

INSTALLED_APPS = [
   ...
   'myapp',
]

If you skip this step, Django will ignore your app.

Step5: Run the server to verify#

python manage.py runserver

Open:

http://127.0.0.1:8000/

If no errors → app created successfully

Step6: (Optional) Create app URLs#

Create a file:

myapp/urls.py

Add:

from django.urls import path
from . import views

urlpatterns = [
   path('', views.home, name='home'),
]

Then include it in project urls.py:

from django.urls import path, include

urlpatterns = [
   path('', include('myapp.urls')),
]

Step7: (Optional) Create your first view#

In myapp/views.py:

from django.http import HttpResponse

def home(request):
   return HttpResponse("Hello from myapp")

Refresh browser

Naming rules for apps#

Good names:

  • blog

  • accounts

  • payments

  • orders

Bad names:

  • MyApp

  • Test-App

  • django

Use:

  • lowercase

  • no spaces

  • no hyphens

Common mistakes to avoid#

  • Running startapp outside project

  • Forgetting to add app to INSTALLED_APPS

  • Using uppercase names

  • Creating one giant app

Where myapp lives#

mysite/
├── myapp/      ← application (features live here)
├── mysite/     ← project configuration
├── manage.py

Why Django uses apps#

Django apps give you:

  • Modular design

  • Reusability

  • Clean separation of concerns

  • Easier testing

  • Enterprise-scale structure

A real Django project often has many apps.

myapp folder structure#

myapp/
├── migrations/
├── __init__.py
├── admin.py
├── apps.py
├── models.py
├── tests.py
├── views.py

We will explain each file separately, check left sidebar navigation.

How myapp connects to the project#

Nothing in myapp works until you register it.

In settings.py:

INSTALLED_APPS = [
   ...
   'myapp',
]
Once added:

  • Models are recognized

  • Migrations work

  • Admin shows your models

  • URLs can connect to views

What myapp is responsible for#

myapp can contain:

  • Database tables (models)

  • Business logic

  • Views (HTTP handling)

  • Admin customization

  • Tests

  • API logic

It does NOT:

  • Configure settings

  • Run servers

  • Handle deployment

Project vs App#

Project (mysite)

App (myapp)

Settings

Features

URLs (root)

URLs (feature-level)

ASGI / WSGI

Views

Deployment

Business logic

Real-world example#

Think like this:

🏢 Project = Mall

🏬 Apps = Shops

  • Mall handles security, electricity, layout

  • Each shop handles its own products and sales

How Django uses myapp#

Request flow:

Browser → urls.py → views.py → models.py → response

All of that happens inside the app.

Very important rule#

One app = one responsibility

Good:

  • accounts

  • orders

  • payments

Bad:

  • One giant app doing everything

What we’ll cover next#

Next pages in this exact order:

  1. migrations/

  2. __init__.py (app-level)

  3. apps.py

  4. models.py

  5. admin.py

  6. views.py

  7. tests.py

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