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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

← Mixpanel

New Grad / Junior Backend at Mixpanel

BackendNew Grad / JuniorOffer◆ Commonly asked· 2024

Junior backend interview. Balanced across coding, design, and collaboration.

The loop · 5 rounds

01

Round 01 · 1 question

Online Assessment

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

  • Group items by frequency and return the top K.
    New Grad / JuniorMedium◆ Commonly asked
    #hashmap#heap
    PracticeGeeksforGeeks↗Search↗
02

Round 02 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Maximum subarray (Kadane).
    New Grad / JuniorMedium◆ Commonly asked
    #array#dp
    PracticeLeetCode↗GeeksforGeeks↗
  • Sliding window maximum.
    New Grad / JuniorHard◆ Commonly asked
    #deque#sliding-window
    PracticeLeetCode↗GeeksforGeeks↗
  • Reverse nodes in k-group.
    New Grad / JuniorHard◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
03

Round 03 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a webhook receiver with signature verification.
    New Grad / JuniorMedium◆ Commonly asked
    #security#api
    PracticeGeeksforGeeks↗Search↗
  • Build a CSV importer that streams and validates rows.
    New Grad / JuniorMedium◆ Commonly asked
    #streaming#validation
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Caching strategies: cache-aside, write-through, TTLs.
    New Grad / JuniorMedium◆ Commonly asked
    #cache
    PracticeGeeksforGeeks↗Search↗
  • How do you design a public API for backward compatibility?
    New Grad / JuniorMedium◆ Commonly asked
    #api-design
    PracticeGeeksforGeeks↗Search↗
  • How would you design and version a public REST API?
    New Grad / JuniorMedium◆ Commonly asked
    #api-design
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 2 questions

Behavioral / HR

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

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

Practice each round across every company

  • Online Assessment
  • DSA / Coding
  • Machine Coding
  • Tech Deep-Dive
  • 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.