Milkbasket Full Stack Developer Interview: Rounds, Questions and Preparation

What the job involves

Full Stack Developers at Indian unicorns and high-growth startups build and maintain both client-side and server-side components of web applications, often working on features that directly impact user experience and operational efficiency. In a quick-commerce or subscription-based company, you might work on customer-facing apps, internal dashboards, or order management systems. Expect to touch code across the stack, collaborate with product and design, and iterate quickly based on data.

Role and Technical Knowledge

1. 1

   Explain the difference between client-side and server-side rendering. When would you choose one over the other for a quick-commerce app?

   Cover performance, SEO, and initial load time. Mention that for a customer-facing app with dynamic content, a hybrid approach like Next.js might be used, while internal dashboards may favour client-side rendering.

2. 2

   How would you design a database schema for a subscription-based grocery delivery service?

   Discuss entities like users, subscriptions, orders, products, and delivery slots. Mention normalization, indexing, and choice between SQL and NoSQL based on query patterns and scale.

3. 3

   What are the key considerations for building a REST API that supports a mobile app and a web dashboard?

   Talk about versioning, authentication, rate limiting, and consistent response formats. Highlight the need for efficiency and pagination for mobile clients.

4. 4

   How do you ensure security in a full stack application, especially when handling user data and payments?

   Mention input validation, HTTPS, secure storage of passwords (hashing), JWT or session management, and PCI compliance for payments. Also touch on avoiding common vulnerabilities like XSS and SQL injection.

Practical Scenarios

1. 5

   You are building a feature to show real-time order tracking. How would you implement it?

   Suggest WebSockets or polling, and discuss trade-offs. Mention backend events, message queues, and frontend state management. Consider scalability and fallback mechanisms.

2. 6

   A page on your app is loading slowly. How would you debug and improve its performance?

   Cover frontend optimisation (minification, lazy loading, image compression) and backend optimisation (database indexing, caching, query optimisation). Mention using browser dev tools and monitoring tools.

3. 7

   You need to integrate a third-party payment gateway. What steps would you take?

   Discuss reading API docs, setting up sandbox testing, handling callbacks and webhooks, error handling, and ensuring idempotency. Also mention security and compliance.

4. 8

   How would you handle a situation where the frontend and backend teams have different assumptions about an API contract?

   Emphasise communication, using tools like Swagger/OpenAPI for documentation, and agreeing on a contract first. Mention mock servers and contract testing.

Behavioral and HR

1. 9

   Tell me about a time you had to learn a new technology quickly for a project.

   Use STAR method. Highlight your learning process, resourcefulness, and how you applied the new skill to deliver results.

2. 10

   Describe a situation where you disagreed with a teammate. How did you handle it?

   Show respect, active listening, and focus on data or user impact. Conclude with a positive outcome or compromise.

3. 11

   Why do you want to work at a high-growth startup like Milkbasket rather than a large established company?

   Express enthusiasm for fast-paced environments, ownership, and learning opportunities. Align with the company's mission and your career goals.

4. 12

   How do you prioritise tasks when you have multiple deadlines?

   Discuss using urgency and importance, communication with stakeholders, and tools like Trello or Jira. Give an example of a time you managed conflicting priorities.

Coding and Problem Solving

1. 13

   Write a function to find the first non-repeating character in a string.

   Use a hash map to count frequencies, then iterate to find the first with count 1. Discuss time and space complexity.

2. 14

   Given an array of integers, find two numbers that add up to a target sum.

   Use a hash set for O(n) time. Explain the approach and handle edge cases like no solution.

3. 15

   How would you reverse a linked list?

   Iterative approach with three pointers. Explain step by step and mention recursive alternative. Discuss time O(n) and space O(1) for iterative.

4. 16

   Implement a stack that supports push, pop, and retrieving the minimum element in O(1) time.

   Use two stacks or a single stack with pairs. Explain the logic and complexity.