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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

← Perplexity

New Grad / Junior Backend at Perplexity

BackendNew Grad / JuniorNo offer◆ Commonly asked· 2023

5-round junior backend process. Fast-paced; expect follow-ups that push on depth.

The loop · 5 rounds

01

Round 01 · 1 question

Online Assessment

Timed online coding / aptitude screen, usually the first filter.

  • Count pairs with a given sum in an array.
    New Grad / JuniorEasy◆ Commonly asked
    #hashmap
    PracticeGeeksforGeeks↗Search↗
02

Round 02 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Word search II.
    New Grad / JuniorHard◆ Commonly asked
    #trie#backtracking
    PracticeLeetCode↗GeeksforGeeks↗
  • Coin change — fewest coins to make an amount.
    New Grad / JuniorMedium◆ Commonly asked
    #dp
    PracticeLeetCode↗GeeksforGeeks↗
  • Combination sum.
    New Grad / JuniorMedium◆ Commonly asked
    #backtracking
    PracticeLeetCode↗GeeksforGeeks↗
03

Round 03 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Implement a leaderboard API backed by a sorted set.
    New Grad / JuniorMedium◆ Commonly asked
    #redis#ranking
    PracticeGeeksforGeeks↗Search↗
  • Implement a bulk-upsert endpoint with validation.
    New Grad / JuniorMedium◆ Commonly asked
    #api#validation
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Explain how DNS resolution works end to end.
    New Grad / JuniorMedium◆ Commonly asked
    #networking
    PracticeGeeksforGeeks↗Search↗
  • Difference between at-least-once and exactly-once delivery.
    New Grad / JuniorHard◆ Commonly asked
    #messaging
    PracticeGeeksforGeeks↗Search↗
  • How do you design a public API for backward compatibility?
    New Grad / JuniorMedium◆ Commonly asked
    #api-design
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 2 questions

Behavioral / HR

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

  • How do you handle competing priorities from two managers?
    New Grad / Junior◆ Commonly asked
    #prioritization#star
  • Describe mentoring or unblocking another engineer.
    New Grad / Junior◆ Commonly asked
    #mentorship#star

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