3 rounds: pure technical with an SDE3 (Websockets, rate limiter, DSA, SQL/NoSQL), System Design, EM round

Application

I applied online. The process took 1 day. I interviewed at Zomato (Gurgaon, Haryana) in Sept 2025

Interview

Three rounds were scheduled, first pure technical, second technical and mostly System Design, third with Engineering Manager. A SDE 3 took the first round, was chill wholesome guy, told me to be friendly and not be nervous, started with discussion on my projects, what, whys and hows, discussed about Websockets and authentication, then designing a rate limiter for API gateway, optimized with Redis. Then we went to DSA, he asked two simple questions, one was with string and arrays which i solved, optimized but best solution was with Tries which i give. Some simple SQL and NoSQL discussion, then some networking, Throttling, ended with general discussion, culture and expectations. I was expecting that i cleared this round and was very confident for System Design round. Well I couldn't clear it, what I think is they expect full clarity and almost perfect answers, so if you seem a little confused or not direct it won't help it.

Interview questions [2]

Question 1

Designing and optimizing a rate limiter