Beyond the Django Tutorial

Django is famous for its excellent documentation and the "Polls App" tutorial. Because of this, many junior Python developers claim to be Django experts. However, building a production-ready Django API requires deep knowledge of database optimization, security, and asynchronous tasks. Here is how to vet them.

1. The N+1 Query Problem

Ask them: "What is the N+1 query problem, and how do you solve it in Django?"

This is the most critical question. If they don't know the answer, their APIs will crash your database under load. The correct answer must involve select_related() (for foreign keys) and prefetch_related() (for many-to-many relationships) to optimize SQL queries.

2. Fat Models vs. Fat Views

Ask them: "Where do you put your business logic in a Django app?"

Junior developers put complex logic in the views.py. Senior developers advocate for "Fat Models, Thin Views" (putting logic on the model methods) or using a dedicated "Services" layer to decouple business logic entirely from the HTTP request/response cycle.

3. Django REST Framework (DRF)

Ask them: "How do you optimize a slow DRF endpoint?"

They should mention database optimization first (as per the N+1 problem). Then, they should discuss optimizing serializers (avoiding SerializerMethodField for heavy operations) and finally, implementing caching (using Redis and Django's cache framework).

4. Background Tasks

Ask them: "How do you handle sending an email when a user registers?"

If they say they send the email directly in the view, they fail. Network calls take time; doing it synchronously blocks the server from responding to the user. They must mention using a task queue like Celery with Redis, or Django-Q, to handle it asynchronously in the background.