API Testing for DummyJSON Endpoints using Postman

Introduction

As part of my API testing experience, I worked on testing multiple endpoints from DummyJSON, a free API for testing and prototyping. I focused on the following resources:

• Auth (User Authentication).
• Products (CRUD operations on products).
• Todos (Task management).
• Quotes (Retrieving random or category-based quotes).

Using Postman, I tested various HTTP methods, validated response structures, ensured proper error handling, and verified the relationships between different resources (nested endpoints). Below is a detailed breakdown of my approach and findings.

Test Approach

1️⃣ Setting Up the Postman Collection
I created a Postman Collection named "DummyJSON API Tests" and structured it into folders:

✅ Auth
✅ Products
✅ Todos
✅ Quotes

Each folder contained multiple requests for different API operations, such as GET, POST, PUT and DELETE.

2️⃣ Status Code & Response Validation

For each test, I ensured proper status codes and error messages:

• 200 OK for successful retrieval.
• 201 Created for successful creation.
• 400 Bad Request for missing/invalid data.
• 404 Not Found for non-existent resources.
• 401 Unauthorized for failed authentication.

I also validated the response body structure, ensuring that required fields such as id, title, message, and status were present and correctly formatted.

Conclusion

This testing process improved my understanding of API workflows, CRUD operations, authentication, and error handling. Using Postman, I successfully validated multiple scenarios, ensuring DummyJSON's API performed as expected.

View the detailed DummyJSON's API report here and complete Postman collection here