Site Reliability Engineer Interview Experience at PhonePe – 2025

This online test covers DSA problems and computer network fundamentals, confirmed as the real first stage of PhonePe's campus SRE process. The DSA portion has two problems on arrays and recursion. The networking portion asks conceptual multiple-choice and short-answer questions on IP addressing and basic protocol behavior.

This round covers computer networking theory in real depth: DNS resolution step by step from a client query to an authoritative answer, the OSI model layer by layer with a specific question on which layer a switch operates at versus a router, and DHCP's four-step handshake (Discover, Offer, Request, Acknowledge) for a client obtaining an IP address on a new network. The round also touches shell scripting basics - writing a one-liner to find and kill a process holding open a specific port.

This second technical round focuses further on shell scripting tasks - writing a script to monitor disk usage and alert if it crosses a threshold - and a coding problem asking for mirroring a binary tree recursively (swapping the left and right subtree at every node), best solved with a straightforward recursive approach, mirroring both subtrees first and then swapping the references.

This closing HR round asks directly why the candidate wants to join PhonePe specifically and why the SRE role over a pure software development role, especially when a resume shows a mix of both kinds of internship experience.