My Paytm Senior Software Engineer Interview Experience: 2025

Overview

This case study outlines the interview process for a Senior Software Engineer position at Paytm. The candidate applied through a referral and progressed through several rounds, including an online assessment, technical interviews, and a final round focused on system design.

Interview Rounds

Round 1: Online Assessment

The online assessment was conducted on the HackerRank platform and comprised three sections:

• Data Structures and Algorithms (DSA)
• Multiple Choice Questions (MCQ) - 6 questions
• React-based Machine Coding

Round 2: Technical Interview

The first technical round centered on core data structures and algorithms, complemented by fundamental frontend concepts. Key areas included:

• Implementing a map polyfill in JavaScript, assessing the candidate's grasp of JavaScript objects and data handling.
• Solving a problem to identify the largest duplicate number within an array, evaluating array manipulation and algorithmic skills.
• Logical reasoning questions designed to gauge problem-solving methodologies.
• CSS questions to assess styling expertise.
• Basic HTML questions to confirm a solid frontend foundation.

Final Round

This round involved a discussion of the candidate's prior projects and a Low-Level Design (LLD) discussion, with an emphasis on designing scalable and modular systems. The candidate was also evaluated on asynchronous JavaScript concepts. The candidate addressed a challenge simulating the asynchronous fetching of user details, demonstrating promise handling and error management.

Key Takeaways

While the candidate was ultimately not selected, the interview process highlighted Paytm's focus on fundamental data structures and algorithms, frontend proficiency, and system design principles. The process underscored the importance of a strong understanding of JavaScript, including asynchronous programming, and the ability to apply these concepts to practical problem-solving scenarios.