Phonepe YOE 5
Summary
I interviewed for a Backend Engineer position at PhonePe, completed machine coding, two LeetCode problems, a system design round, and an HR round, and was ultimately rejected.
Full Experience
Recently applied for interview at PhonePe for the backend engineer. Sharing interview experience below.
- Machine coding: Journey service - Not that difficult question. There are multiple journeys, each journey has multiple stages. A user start from the first stage of the journey and move to the next stage when a new event comes and if stage criteria is met. Few easy follow ups during evaluation round and questions on concurrency. Passed the round.
- 2 Leetcode question: https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix/description/ & https://leetcode.com/problems/evaluate-division/description/. Was able to complete the first question with implementation. Second one couldn't write the entire code within the time. Passed the round.
- Design round: Asked to design a feature flag sort of system for PhonePe where any change in flag reflects to million of PhonePe users instantly. similar to https://youtu.be/GsRR__fz854?si=Rnb-TDQ4kUtU7rHm and https://youtu.be/VBCYqp8l3Lc?si=VTr9zKrQij-RsAnA I think my design was not that well in this round and most likely the reason behind reject as per the TA.
- HM round: Standard stuff - previous projects, some behaviour questions around day to day working etc. Deep dive into a design of one of my previous companies project.
Final verdict: Reject.
Yoe 5
Interview Questions (4)
Journey Service Machine Coding
Multiple journeys, each journey has multiple stages. A user starts from the first stage of the journey and moves to the next stage when a new event arrives and if the stage criteria is met. Follow‑up questions on concurrency were also asked.
Kth Smallest Element in a Sorted Matrix
Find the k‑th smallest element in an n × n matrix where each row and each column is sorted in ascending order.
Evaluate Division
Given a list of equations like a / b = 2.0 and queries, evaluate the division results for each query.
Feature Flag System Design
Design a feature flag system for PhonePe where any change in a flag propagates instantly to millions of users. References were provided to videos describing similar systems.