Zerto India Software Engineer Interview: Rounds, Questions and Preparation

What the job involves

Software Engineers at fast-growing global tech product companies like Zerto India build and maintain features for distributed systems, often focusing on data protection, cloud infrastructure, or storage. Day to day they write code, review pull requests, debug production issues, and collaborate with product and QA teams. Freshers typically start with well-scoped tickets and gradually take ownership of modules.

Role and Technical Knowledge

1. 1

   What is the difference between a process and a thread, and how does it affect performance in a multi-threaded server?

   Explain memory sharing, context switching overhead, and give a concrete example like a web server handling concurrent requests.

2. 2

   How would you design a simple key-value store that supports get, put, and delete operations?

   Cover data structures like hash maps, persistence options, and trade-offs between in-memory and disk-based storage.

3. 3

   Explain ACID properties in a database and why they matter for a backup or replication system.

   Define each property and connect it to data integrity during failure scenarios, which is critical for data protection products.

4. 4

   What happens when you type a URL into a browser and press Enter, from DNS to rendering?

   Walk through DNS resolution, TCP handshake, HTTP request, server response, and browser rendering in a structured way.

Practical Scenarios

1. 5

   You are asked to debug a service that intermittently returns 500 errors under load. How do you approach it?

   Mention checking logs, metrics, reproducing under load, isolating components, and using tools like strace or profilers.

2. 6

   Given a large log file, how would you find the top 10 most frequent IP addresses efficiently?

   Describe a streaming approach with a hash map, then a heap for top K, and discuss memory constraints.

3. 7

   How would you implement a rate limiter for an API endpoint?

   Discuss token bucket or sliding window algorithms, and where to store state (in-memory vs Redis).

4. 8

   You need to write a script to automate backup of a directory to a remote server daily. What steps and tools would you use?

   Cover cron, rsync or scp, error handling, logging, and verification of backup integrity.

Behavioural and HR

1. 9

   Tell me about a time you had to learn a new technology quickly for a project. How did you go about it?

   Use STAR method, highlight self-learning resources, and show measurable outcome like meeting a deadline.

2. 10

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

   Focus on respectful communication, data-driven discussion, and willingness to compromise for the team's goal.

3. 11

   Why do you want to work at a fast-growing product company like Zerto India rather than a large service-based firm?

   Show interest in ownership, product impact, and learning opportunities in a smaller, agile environment.

4. 12

   Where do you see yourself in three years, and how does this role fit your goals?

   Align your growth with technical depth, taking ownership, and contributing to the company's product roadmap.

Problem Solving and Coding

1. 13

   Given an array of integers, find two numbers that sum to a target. Discuss time and space complexity.

   Explain brute force O(n^2) vs hash map O(n) approach, and handle edge cases like duplicates.

2. 14

   Reverse a linked list iteratively and recursively. Which is better and why?

   Show both implementations, compare space complexity, and discuss stack overflow risk in recursion.

3. 15

   Implement a function to check if a binary tree is a binary search tree.

   Use in-order traversal or range checking, and explain why comparing only with immediate children is insufficient.

4. 16

   How would you find the first non-repeating character in a string?

   Use a hash map to count frequencies, then a second pass, and discuss Unicode vs ASCII assumptions.