During a 60-minute HackerRank online interview, I was given a single large system-design problem divided into five parts: to build a server load-balancing system. My task was to design data structures and algorithms that could maintain a pool of servers and distribute client connections according to a chosen balancing policy such as least-loaded, round-robin, or consistent hashing. A key requirement was to implement a tdown operation, which shuts down a specified server by its ID and then reassigns all existing connections on that server to other servers using the same logic as the normal CONNECT operation, ensuring consistent and balanced redistribution. Over the course of the exercise I needed to think through the full lifecycle—tracking servers and connections, handling edge cases like the absence of available servers, and optimizing for both time and space efficiency—while writing working code for each of the five progressive parts.
Interview questions [1]
Question 1
Design a server load-balancing system.
You need to build the core data structures and logic that manage a pool of servers and distribute client connections across them according to some rules (not all the rules are written out here, but think along the lines of “CONNECT” requests and balancing algorithms).
One of the specified operations is called tdown:
tdown can shut down a given server identified by an ID or sequence number.
When a server is shut down, any existing client connections on that server must be re-assigned to other servers.
The re-assignment must follow the same rules as a normal CONNECT operation—i.e., whatever balancing strategy you defined for new connections (e.g., least-loaded, round-robin, consistent hashing) must be used to redistribute those connections.
First an OA which is very hard, you have to be really fast. Then HR call and then phone round. Unfortunately I got unlucky and my interviewer was doing something else while doing the interview, he was muted and I had to ask for his attention twice. Of course in the end he said I did very well and one day later I was rejected. The phone round is not particularly difficult but you have to be fast and talking too much will cost you.
Interview questions [1]
Question 1
They have a bunch of questions about string parsing, more often than not you will need to read a CSV so know how to do that, and know how to use the split function.
1 round of team screen - go/no go with a multi step problem
Design - classic interview
Integration - work on integrating some new systems
Bug bash - find and solve a bug
Programming exercise - same as team screen maybe a bit harder
I applied through a recruiter. I interviewed at Stripe in Jul 2026
Interview
started with a quick recruiter chat (checking developer infrastructure know-how), followed by a 45-min live coding screen where they look for production ready code. onsite was 5 rounds: coding, bug bash, integration, system design, and behavioral. bug bash was the most interesting part. they just drop you into a random repo with failing tests and watch how you track down the root cause. integration is pure API work - reading docs and wiring things up, but they lean heavy on error handling. sys design felt very grounded. instead of drawing huge scalable architecture, we basically just talked through failure modes and backward compatibility.behavioral was standard. across the board, stripe cares way more about readable code and communication than tricky algorithms.for prep, practice reading other people's code and fixing bugs. i had a mock on prepfully with a stripe SWE to test my bug bash process, and it really highlighted some messy debugging habits i had. tough loop, but it actually feels like real engineering.
Interview questions [1]
Question 1
Given a stream of Stripe checkout session events, identify sessions abandoned at each step of the checkout flow and calculate conversion rates