Upstox Senior Software Engineer Interview Questions and Answers

Developed a web application for online shopping with user authentication and payment gateway integration.

• Used React.js for front-end development

• Implemented user authentication using JWT tokens

• Integrated Stripe API for payment processing

Optimization techniques are methods used to improve the efficiency and performance of software applications.

• Use of algorithms like dynamic programming and greedy algorithms

• Profiling and performance tuning to identify bottlenecks

• Code refactoring to improve readability and maintainability

• Utilizing caching and memoization for faster access to data

• Parallel processing and multi-threading for improved concurrency

Find k closest elements in an array

• Sort the array based on the absolute difference between each element and the target element

• Return the first k elements from the sorted array

Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Create a private static instance variable of the class.

• Make the constructor private to prevent instantiation from outside the class.

• Provide a static method to get the instance, creating it if necessary.

Designing WhatsApp involves creating a high-level design for the messaging app, focusing on features like chat, groups, calls, and media sharing.

• Implement chat functionality with real-time messaging using sockets

• Design group chat feature with ability to add/remove members

• Include end-to-end encryption for secure messaging

• Develop voice and video calling functionality

• Allow media sharing such as photos, videos, and documen

Design a ticket booking system for efficient and user-friendly experience.

• Use a database to store information about available tickets, users, and bookings

• Implement a user-friendly interface for users to search for and book tickets

• Include features like seat selection, payment processing, and booking confirmation

• Consider scalability and performance to handle a large number of users and bookings