Zomato SDE Interview Experience

Profile: Final-year student at a Tier-1 college, Delhi
Round Type: Off-Campus | SDE Role
Status: Selected
Applied Via: Cold Mail to Deepinder Goyal (Zomato CEO)

Round 1: Technical Interview (CS Fundamentals + DSA + Resume Deep-Dive)

A deep-dive technical round covering resume discussions, system design, CS fundamentals, and DSA problems.

Resume & Work Experience Discussion:

• USA-based startup experience – Projects & technical implementations
• Multithreading & concurrency – How I leveraged them in my work

CS Fundamentals & System Design:

1. SQL vs NoSQL – Differences, use cases, and scalability considerations
2. Thread vs Process – Key differences, advantages, and when to use each
3. Inter-Process Communication (IPC) – Shared Memory, Pipes, Message Queues, Semaphores, Mutexes
4. Thread Lifecycle – New, Runnable, Blocked, Waiting, Timed Waiting, Terminated
5. UDP vs TCP – Differences, real-world applications, and trade-offs
6. What happens when you type zomato.com in a browser? – Full breakdown from DNS resolution to page rendering
7. Database Indexing – Various types and internal implementations

Sorting & Algorithmic Concepts:
8. Quick Sort vs Merge Sort – Time complexity, stability, and practical use cases
9. Multithreaded Merge Sort – Parallelizing merge sort using multiple threads
10. O(1) Space Merge Sort – Optimizing merge sort with constant space
11. Modified Merge Sort on Multi-Core vs Single-Core CPU
12. Heap vs Sorting – When to prefer heaps over traditional sorting
13. Heap Pseudocode – Insert, delete, heapify with time & space complexity analysis

Security & System Design:
14. JWT (JSON Web Token) – Structure, security, and authentication flow

DSA Coding Problems:
15. Greedy Problem (Priority Queue-based) – Required a non-trivial greedy approach
16. Graph-based Variation of the Above Problem – Required Prim's Algorithm (MST)

Interviewer Feedback: "You're a great candidate, focusing on breaking the larger problem into smaller chunks." Performance Rating: 9.8/10. Received a call for Round 2 after four working days.

Round 2: System Design + Resume Deep-Dive

Resume Discussion & Multiprocessing Concepts:

• Scalability of my projects – Handling concurrent users
• Multiprocessing vs Multithreading – Key differences and implementations

System Design Question: Rate Limiter
Problem: Design a Rate Limiter for an API
Approach: Fixed Window & Sliding Window – Implemented using Redis and log storage. Leaky Bucket & Token Bucket – Discussed trade-offs and real-world applications.

System Design Question: Order Processing API
Problem: Design an API to process incoming order batches, where each batch contains multiple orders with different timestamps. The API should allow querying the number of orders in the last X minutes (up to 30 minutes).
Approach: Fixed array of 30 buckets, each representing one minute. Orders placed in corresponding buckets based on their timestamp. Timestamp array ensures outdated buckets are reset. Querying last X minutes = summing relevant buckets. Used ReentrantLock for thread safety.

Interviewer Feedback: "Your structured thought process and implementation were spot-on. Well done!" Performance Rating: 9.5/10. Received a call for Round 3 after four working days.

Round 3: Culture Fit Round (Onsite)

This round was with the VP of Tech at Zomato and focused on:

• Work principles – Ownership, fast-paced work, and user-centric thinking
• Detailed discussion on my work experience

The round was short as my prior feedback was excellent. Offer was rolled out immediately!

PS: Expert (1740+) on Codeforces, 5-Star (2000+) on CodeChef, Guardian (2390+) on LeetCode