Master Serializers, ViewSets, and JWT Security with Real-World DRF Interview Questions and Detailed Explanations.

Course Description

Django REST Framework (DRF) Interview Practice Questions are meticulously designed to bridge the gap between basic CRUD knowledge and the high-level architectural expertise required for senior backend roles. Whether you are preparing for a rigorous technical interview or looking to validate your skills for a professional certification, this course provides a deep dive into the "why" behind the code, covering everything from the internal request-response lifecycle and complex nested serialization to advanced security patterns like OAuth2 and JWT. By working through scenario-based challenges, you will learn to optimize performance using select_related and prefetch_related, implement robust object-level permissions, and structure clean, scalable business logic using ViewSets and custom Actions. This isn't just a list of questions; it's a comprehensive training ground that ensures you can confidently explain your technical decisions to hiring managers and lead developers alike.

Exam Domains & Sample Topics

Core Architecture: Request/Response objects, Parsers, Renderers, and APIView vs. GenericAPIView.
Data Modeling: Nested Serializers, to_representation, and custom field validation.
Security: JWT/SimpleJWT, Throttling, and Custom Permission classes.
ViewSets & Routing: Routers, @action decorators, and Service Layer patterns.
Optimization & Testing: N+1 query fixes, APITestCase, and Swagger integration.

Sample Practice Questions

1. When overriding the to_internal_value method in a Serializer, what is its primary responsibility? A. To convert the model instance into a JSON-serializable dictionary. B. To validate and transform the incoming primitive data into Python-native types. C. To handle the final save() logic for the database. D. To provide a read-only representation of a specific field. E. To bypass the default validate_<field_name> methods. F. To automatically trigger the post_save signal.

Correct Answer: B

Overall Explanation: to_internal_value is the entry point for validation and deserialization. It takes the raw data (usually a dict) and converts it into the validated data used by the serializer.
Option A Incorrect: This describes to_representation.
Option B Correct: This is the core definition of the method's role in the lifecycle.
Option C Incorrect: Saving is handled by the create() or update() methods.
Option D Incorrect: Read-only logic is usually handled by field arguments or to_representation.
Option E Incorrect: It does not bypass them; it typically runs before them.
Option F Incorrect: Signals are triggered by the model's save() method, not this serializer hook.

2. To solve an N+1 query problem in a DRF ViewSet that lists a model with a Foreign Key relationship, which approach is most efficient? A. Iterate through the queryset and call .save() on each object. B. Use self.queryset.all() and let the Serializer handle the nesting. C. Override get_queryset to include .select_related() for the foreign key. D. Increase the PAGE_SIZE in the settings. E. Use prefetch_related() for one-to-one relationships specifically. F. Disable the renderer and return raw SQL.

Correct Answer: C

Overall Explanation: Optimization in DRF often happens at the QuerySet level to ensure the database join happens in a single query rather than multiple recursive queries.
Option A Incorrect: This would actually create more database overhead.
Option B Incorrect: This is the default behavior that causes the N+1 problem.
Option C Correct: select_related performs a SQL join, effectively fetching the related data in one go.
Option D Incorrect: Pagination size does not change the efficiency of the individual record fetching.
Option E Incorrect: select_related is generally better for foreign keys (forward relationships); prefetch_related is for many-to-many or reverse lookups.
Option F Incorrect: This is unnecessary and defeats the purpose of using DRF.

3. Which status code is traditionally returned by a DRF APIView when a request fails due to a throttled (rate-limited) user? A. 401 Unauthorized B. 403 Forbidden C. 400 Bad Request D. 429 Too Many Requests E. 503 Service Unavailable F. 404 Not Found

Correct Answer: D

Overall Explanation: Standard HTTP status codes are used by DRF to communicate the nature of the failure to the client.
Option A Incorrect: 401 is for missing or invalid authentication.
Option B Incorrect: 403 is for authenticated users who lack permissions.
Option C Incorrect: 400 is for malformed syntax or validation errors.
Option D Correct: 429 is the standard HTTP code for rate limiting/throttling.
Option E Incorrect: 503 is for server-side downtime.
Option F Incorrect: 404 is for resources that do not exist.

Welcome to the best practice exams to help you prepare for your Django REST Framework (DRF) Interview Practice Questions.
- You can retake the exams as many times as you want
- This is a huge original question bank
- You get support from instructors if you have questions
- Each question has a detailed explanation
- Mobile-compatible with the Udemy app
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We hope that by now you're convinced! And there are a lot more questions inside the course. Enroll today and take the final step toward getting certified!