Final year CSE student at a Tier-3 University
Applied off-campus through a referral

Offered Intern + FTE as SDE-I

ROUND 1

This was a mix of system design, DB reasoning, API thinking, and general backend engineering concepts. The interviewer focused on how I approach design decisions rather than knowing everything perfectly.

1. Introduction + Projects

I started with a quick intro and walked through my backend projects. The interviewer immediately went into deeper questions about design choices, scaling, and modularity.

2. What I Knew About Zomato + Nugget

He asked what I understood about Zomato as a product and how teams like Nugget fit into the company’s ecosystem. I talked about the ordering workflow, discovery, restaurant onboarding, AI customer support, ticket handling, etc.

3. System Design – Online Ordering

We jumped straight into designing the online ordering flow.

User side flow

• Login
• Restaurant discovery based on location
• Selecting items from menu
• Placing order

Restaurant manager side flow

• Manager login
• Managing multiple restaurants (many-to-many relationship)
• Menu updates

He asked me to structure:

• Each API call
• Sample request/response payloads
• Backend processing steps
• DB schema choices

4. SQL vs NoSQL Discussion

He asked which DB I would pick for the ordering system.
I chose SQL, and we discussed:

• Why SQL for strongly consistent flows
• When NoSQL becomes useful
• Tradeoffs in scalability
• Joins vs denormalized data

5. Geographical Data Handling

He asked how to list nearby restaurants using SQL.
I could answer the basics (lat/long, bounding box), but he pushed for deeper details (geo-indexing, PostGIS).
I wasn’t fully confident here and he wasn’t 100% satisfied.

6. Manager-Restaurant Mapping

We discussed:

• First we started with one-to-one mapping from restaurant to manager
• Interviewer then asked to go to many-to-many mapping
• I made a mapping table in between that has manager_ID and restaurant_ID as Foreign Keys referencing Manager table and Restaurant table
• How managers see all restaurants under them
• How data is fetched efficiently per login

7. Coding Practices

We covered clean modular backend structure:

• Service + Controller layers
• Error handling

8. S3 Image Uploads

• He asked how will I upload images
• I said we can use base64 encoding
• He asked me how will I manage big images here
• He was lookingg for the concept of pre-signed URLs but I wasn't aware of it completely, was told to read about it later

Overall, this round was conversational, detailed, and focused on clarity of design thinking and how one attempts to solve problems. Not purely correctness.

ROUND 2 (Onsite)

This was more intense and covered system design, databases, message brokers, and DSA.

1. Brief Introduction

She stopped early and directly jumped into discussing my backend internship:

• How the system was designed
• I drew it and said that we are building it from scratch in phase 2
• Was asked how do we plan to rebuild phase 2 from scratch
• What improvements I would bring
• Drew out system design for phase 2
• I could see she wasn't a 100 percent in agreement

2. Architecture & Microservices of Personal Projects

We discussed:

• Why partial microservices
• Communication flow
• When monolith is better
• When to split services

3. Message Broker Discussion

We talked about:

• RabbitMQ
• Redis streams
• Very brief Kafka discussion

I clarified that I only had a basic understanding of Kafka and didn’t want to overclaim. She appreciated the honesty.

4. Rate Limiter Design

She asked:

• What is a rate limiter?
• Implement a simple one
• Then discussed sliding window approach
• I wrote pseudocode and walked through how it prevents bursts.

5. Real-Time Support Chat Design Problem

• Started with 1-to-1 chat between customer and agent
• Then move to multi-user groups
• Then message visibility & permissions

We also discussed:

• When SQL works
• When NoSQL (MongoDB) is better
• Why chat systems lean toward NoSQL

6. MongoDB Deep Dive

Questions included:

• How MongoDB indexing works
• How compound indexes work and follow the left-prefix rule
• Write a MongoDB query (I explained the logic but couldn’t write it perfectly)

7. DSA Problem

Problem: Longest valid parenthesis subsequence (discontinuous)
I initially suggested a few wrong approaches, corrected them, and then reached an acceptable solution.
I handwritten dry-ran each approach with pen and paper.

8. My Question to the Interviewer

They asked if I had any questions.
I asked how Zomato handles external outages like the Cloudflare outage that happened 2 hours before, which took Blinkit and others down for ~5 minutes.
We had a short but interesting discussion about resilience and fallback strategies.

ROUND 3 (Onsite)

This round was with the VP of Technology and was mostly a culture + team fit discussion.

We talked about:

• My motivations
• Work style and ownership
• Fallbacks (following the Cloudflare discussion)
• Joining timelines and formalities

This is where I was officially extended the offer.
I also asked a few questions about the team structure and how backend squads collaborate.

This was my overall interview experience for the Backend Intern + SDE-I role at Zomato.