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Interview questions from top companies, mapped to the exact round they show up in. Prep for what you will actually face.

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Online AssessmentDSA / CodingMachine CodingLow-Level Design

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The Loop aggregates publicly shared interview experiences and curated commonly-asked questions, each labeled with its source. Not affiliated with any company listed.

CC BY-NC 4.0 · © 2026

← Palo Alto Networks

Senior Backend at Palo Alto Networks

BackendSeniorOutcome unknown◆ Commonly asked· 2024

6-round senior backend process. Balanced across coding, design, and collaboration.

The loop · 6 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Pow(x, n).
    SeniorMedium◆ Commonly asked
    #math#recursion
    PracticeLeetCode↗GeeksforGeeks↗
  • Construct binary tree from preorder and inorder traversal.
    SeniorMedium◆ Commonly asked
    #tree#recursion
    PracticeLeetCode↗GeeksforGeeks↗
  • Sliding window maximum.
    SeniorHard◆ Commonly asked
    #deque#sliding-window
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Implement an exponential-backoff HTTP client.
    SeniorMedium◆ Commonly asked
    #reliability
    PracticeGeeksforGeeks↗Search↗
  • Build a background job runner with priorities.
    SeniorMedium◆ Commonly asked
    #queue#workers
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a rate limiter for a public API.
    SeniorMedium◆ Commonly asked
    #token-bucket#redis
    PracticeGeeksforGeeks↗Search↗
  • Design a chat/messaging backend with delivery guarantees.
    SeniorHard◆ Commonly asked
    #websocket#queues
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • How do you run a zero-downtime database migration?
    SeniorHard◆ Commonly asked
    #databases
    PracticeGeeksforGeeks↗Search↗
  • How do you design an idempotency-key system for payments?
    SeniorHard◆ Commonly asked
    #idempotency#payments
    PracticeGeeksforGeeks↗Search↗
  • How do circuit breakers and bulkheads improve resilience?
    SeniorMedium◆ Commonly asked
    #reliability
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

Scope, ownership, and role-fit discussion with the manager.

  • How do you decide what to build vs. buy vs. defer?
    Senior◆ Commonly asked
    #judgment
06

Round 06 · 2 questions

Behavioral / HR

Values, collaboration, and past-experience (STAR) questions.

  • Tell me about a time you simplified something overly complex.
    Senior◆ Commonly asked
    #judgment#star
  • Describe a goal you set and how you achieved it.
    Senior◆ Commonly asked
    #ownership#star

Practice each round across every company

  • DSA / Coding
  • Machine Coding
  • System Design
  • Tech Deep-Dive
  • Hiring Manager
  • Behavioral / HR

◆ This experience is composed from commonly reported questions for this role and level. Real, individually-shared interviews will be layered in over time.