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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

← Zscaler

Senior Backend at Zscaler

BackendSeniorOffer◆ Commonly asked· 2024

Senior backend interview. Pragmatic questions — more real-world than pure puzzles.

The loop · 6 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Diameter of a binary tree.
    SeniorEasy◆ Commonly asked
    #tree#dfs
    PracticeLeetCode↗GeeksforGeeks↗
  • Container with most water.
    SeniorMedium◆ Commonly asked
    #two-pointers#array
    PracticeLeetCode↗GeeksforGeeks↗
  • Reverse a linked list.
    SeniorEasy◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Parse and evaluate a simple expression/DSL.
    SeniorMedium◆ Commonly asked
    #parsing
    PracticeGeeksforGeeks↗Search↗
  • Build a URL health checker with a concurrency limit.
    SeniorMedium◆ Commonly asked
    #concurrency
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a news feed / timeline.
    SeniorHard◆ Commonly asked
    #fanout#ranking#cache
    PracticeGeeksforGeeks↗Search↗
  • Design a chat application like WhatsApp.
    SeniorHard◆ Commonly asked
    #websocket#fanout#storage
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Explain eventual consistency with a real example.
    SeniorHard◆ Commonly asked
    #distributed
    PracticeGeeksforGeeks↗Search↗
  • Explain how you handle concurrency / race conditions.
    SeniorHard◆ Commonly asked
    #concurrency
    PracticeGeeksforGeeks↗Search↗
  • How do you design a schema for a multi-currency ledger?
    SeniorHard◆ Commonly asked
    #databases#money
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

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

  • How do you set technical direction for a team?
    Senior◆ Commonly asked
    #leadership#strategy
06

Round 06 · 2 questions

Behavioral / HR

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

  • Describe mentoring or unblocking another engineer.
    Senior◆ Commonly asked
    #mentorship#star
  • Tell me about a time you simplified something overly complex.
    Senior◆ Commonly asked
    #judgment#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.