Coupa

Role: SDET (Software Development Engineer in Test)

College: Not Specified

Interview Date: October 2024 (Last Updated: July 23, 2025 on GeeksforGeeks, October 13, 2024 on LeetCode Discuss)

Interview Type: Off-Campus, Full-Time

Result: Selected (Offer Received)

Difficulty: Easy to Medium (OA), Medium (Overall)

Rounds: 1 Online Assessment + 3 Interview Rounds

Topics Asked: Data Structures, Algorithms, OOPs (Inheritance, Abstraction vs Encapsulation, Polymorphism, Virtual Keyword), SQL (challenging queries, joins, database optimization, MySQL vs MongoDB), REST APIs (PUT vs PATCH, GET vs POST), System Design (LLD for elevator system), Frontend Concepts (class-based vs functional components, cookie vs local storage vs session storage, Redux Toolkit, debouncing, lazy loading, caching), Puzzles, Project Discussions, Behavioral (Why Coupa?).

Experience:

The candidate applied off-campus for a Full-Time SDET role.

Online Assessment (OA): The process began with an OA round. It included Multiple Choice Questions (MCQs) and 3 coding questions, which were described as easy to medium difficulty.

Interview Rounds: On the interview day, there were 3 rounds, each lasting 1 hour with an hour's interval between them.

1st Round:

• A coding question to find the missing integer in an array.
• Discussion on OOPs concepts like Inheritance, and the difference between Abstraction and Encapsulation.
• Technical questions related to class-based vs functional components.
• Concepts like cookie vs local storage vs session storage.
• Questions about Redux Toolkit and its working.
• Detailed discussion on projects and work experience.
• Database-related queries, including schema design and API calls.

2nd Round:

• A challenging SQL query that required finding average price with some joins.
• Question on Radix Sort.
• Questions on REST APIs, including PUT vs PATCH and GET vs POST methods.
• Focus on database optimization.
• Discussion on MySQL vs MongoDB—when to use each, and a scenario was given to decide which database would be more suitable for a website and why.
• Designed an LLD (Low-Level Design) for an elevator system.
• More questions on previous projects.

3rd Round:

• Discussion on work at the previous company.
• Continued focus on database optimization and API calls.
• Questions on debouncing, lazy loading, and Caching.
• Coding Problem: Longest Substring Without Repeating Characters (LeetCode problem).
• Puzzle: The classic jar puzzle (find the jar with contaminated pills).
• Walked through the frontend code of projects.
• Explored polymorphism, with a focus on the virtual keyword.
• Finally, the behavioral question "Why Coupa?" was asked.

The overall experience was a mix of DSA, SQL, system design, REST API concepts, and puzzles, with a strong focus on past experience and projects. The candidate received the offer on the same day, just 1.5 hours after completing the interviews.