An Update API allows clients to modify an existing resource in the database. In RESTful APIs, this usually corresponds to a PUT or PATCH request.

In this guide, we’ll walk through how to create an API endpoint to update a book’s details using Django REST Framework.

What is an Update API?

An Update API modifies data for a single object in the database:

• PUT: Replaces the entire object

• PATCH: Partially updates the object

Example:

PUT /books/1/

Request body:

{
  "title": "Updated Title",
  "author": "Updated Author"
}

Step-by-Step: Create an Update API

We’ll assume you already have a Book model and are using Django REST Framework.

1. Ensure You Have the Book Model

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

class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.CharField(max_length=100)

    def __str__(self):
        return self.title

Migrate if needed:

python manage.py makemigrations
python manage.py migrate

2. Create the Serializer

# books/serializers.py
from rest_framework import serializers
from .models import Book

class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = '__all__'

3. Create the UpdateAPIView

# books/views.py
from rest_framework.generics import UpdateAPIView
from .models import Book
from .serializers import BookSerializer

class BookUpdateView(UpdateAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

✅ UpdateAPIView handles both PUT and PATCH requests for updating a model instance.

4. Add the URL Route

# books/urls.py
from django.urls import path
from .views import BookUpdateView

urlpatterns = [
    path('books/<int:pk>/update/', BookUpdateView.as_view(), name='book-update'),
]

Include it in the main project URL:

# myapi/urls.py
from django.urls import path, include

urlpatterns = [
    path('api/', include('books.urls')),
]

✅ Testing the Update API

Start the server:

python manage.py runserver

Test via curl, Postman, or DRF web interface:

PUT Request – full update:

PUT http://127.0.0.1:8000/api/books/1/update/

Body:

{
  "title": "New Title",
  "author": "New Author"
}

PATCH Request – partial update:

PATCH http://127.0.0.1:8000/api/books/1/update/

Body:

{
  "title": "Only Title Changed"
}

Response:

{
  "id": 1,
  "title": "Only Title Changed",
  "author": "New Author"
}

✅ Summary

⚠️ Common Pitfalls

Tips

• Use PATCH when updating only a few fields to reduce payload size.

• Customize validation with validate_<field> or validate() in the serializer.

• Use Django admin to create initial objects for testing.

• Combine multiple views using ModelViewSet for cleaner architecture.

What’s Next?

Now that you've built a working Update API, consider implementing:

• ✅ Delete API to remove resources

• ✅ Combine List, Retrieve, Create, Update, and Delete into one ModelViewSet

• Add permissions and authentication

• Add unit tests for your views