Palo Alto Networks Software Engineer Interview Experience — Architecture Walkthrough Then Build on Top of It

Palo Alto Networks·Software Engineer·Sep 2025
Onsitemedium

Interview process

  • Introduced ourselves to each other
  • Asked about resume details
  • A simple algorithm warm-up question
  • System design based on the team's existing architecture
  • Q&A for the interviewer

Algorithm question: 226. Invert Binary Tree

Wrote it on the whiteboard and did a dry run.

System design

This team is similar to an ML Infra team — the ML team provides a bunch of models, wraps them into algorithm services, and then backend organizes all of these algorithm services together to serve external users.

So for this round, the interviewer first introduced what models the ML team provides and roughly what the inputs and outputs look like, and then the task was how to string these models together — including how information flows between them, what intermediate storage there is, what the final storage format is, and so on.

During the interview they'd also ask some trade-off questions, like why services talk to each other over RPC instead of a REST API.

I can't really share more specifics here since it directly involves the team's actual architecture, which is too sensitive. But having the interviewer directly walk you through the team's internal architecture and then asking you to build something new on top of it was the first time I'd seen that format — I found it really interesting.

Published

Curated and edited by PracHub

Practice the questions from this interview

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Interview at a glance

Company
Palo Alto Networks
Role
Software Engineer
Rounds
Onsite
Difficulty
medium
Interview date
Sep 2025
Questions from this interview
3 questions

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