I believe I filled out a Google form shared by HR on LinkedIn. The role was for a Senior Backend Engineer, and the location was Mumbai. After a month or so, I got a HackerEarth online test link to be completed in 2 days. I was told that my candidature will be taken forward only upon successful qualification of the online assessment.

Round 0 - Online Coding Assessment (2 hours)

It consisted of 3 DSA questions, revolving around sieve prime factorisation, DFS on connected components, and string palindrome check. I was able to pass all test cases within the stipulated time. After following up with the recruiter around a week later, she replied that I had qualified for the test and would be calling to discuss the next steps. She called the next day and, after asking some basic details, she scheduled the first round for next week.

Technical Round 1 (60 minutes)

This round was taken by a senior backend engineer. The interview structure consisted of introductions, current project-based questions, DSA questions, and resume-based questions.

Project-Based

1. Most complex feature built in the current project.
2. SQL vs NoSQL, ACID vs BASE?
3. Presented some scenarios and asked which DB you would prefer and why? Disadvantages of SQL.
4. Deep dive into blob storage.

DSA

1. LC 39. Combination Sum - expectation was to code the solution and dry run on some test cases.
2. LC 15. 3Sum - expectation was to just explain different approaches and their complexities.

Resume-based

1. Availability, SLA, load balancer, microservices architecture, data replication, etc.
2. Database optimisation techniques.

In the end, I asked about any in-house tools he had been working on in his organisation. More focus was on system design. Overall, the interview feedback was good, hence I was expecting a call for the next round.

After 1 week, I received a call from the recruiter with detailed feedback on my round 1 performance. Appreciate it as very few companies provide feedback, and that too in great detail. The 2nd round was scheduled for the next day.

Technical Round 2 (60 minutes)

This round was taken by an associate director. The round was focused more on system design. It began with introductions and a discussion on my top 3 features built in the current project. I was asked about Kafka brokers, topics, partitions, mechanisms, etc. I was then given a system design problem to create a generic queue system for teams to use. I did not quite understand the description nor how to approach this problem, per se, and once I tried to provide the API design, the interview kept throwing counter questions at whatever I said, to which I could not answer well. In the end, he gave a Java programming problem where we have multiple threads, and at most 2 threads should run in parallel. My multi-threading skills were average, hence I was not very comfortable. It was not a good round as I could not provide the exact solutions the interviewer was expecting and struggled to explain things.

As expected, I received a rejection email later in the day.