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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.

MIT · © 2026

← Reddit

Senior Full-stack at Reddit

Full-stackSeniorOffer◆ Commonly asked· 2024

6-round senior fullstack process. Fundamentals mattered as much as getting to an answer.

The loop · 6 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Sort colors.
    SeniorMedium◆ Commonly asked
    #two-pointers#array
    PracticeLeetCode↗GeeksforGeeks↗
  • Product of array except self.
    SeniorMedium◆ Commonly asked
    #array#prefix-sum
    PracticeLeetCode↗GeeksforGeeks↗
  • Maximum product subarray.
    SeniorMedium◆ Commonly asked
    #array#dp
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a mini ORM query builder (select/where/join).
    SeniorHard◆ Commonly asked
    #parsing#sql
    PracticeGeeksforGeeks↗Search↗
  • Build a form builder that renders from a JSON schema.
    SeniorHard◆ Commonly asked
    #react#forms
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a scalable frontend for an infinite feed (data, caching, rendering).
    SeniorHard◆ Commonly asked
    #frontend#virtualization#cache
    PracticeGeeksforGeeks↗Search↗
  • Design an append-only, queryable audit-log service.
    SeniorMedium◆ Commonly asked
    #storage#immutability
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Explain `useEffect` dependencies and common pitfalls.
    SeniorMedium◆ Commonly asked
    #react#hooks
    PracticeGeeksforGeeks↗Search↗
  • Explain connection pooling and why it matters.
    SeniorMedium◆ Commonly asked
    #databases
    PracticeGeeksforGeeks↗Search↗
  • Explain hydration and the cost of client vs server rendering.
    SeniorHard◆ Commonly asked
    #ssr#perf
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

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

  • How do you measure the success of a project after launch?
    Senior◆ Commonly asked
    #metrics
06

Round 06 · 2 questions

Behavioral / HR

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

  • Describe something you shipped that you were not proud of.
    Senior◆ Commonly asked
    #tradeoffs#star
  • How do you handle being blocked for several days?
    Senior◆ Commonly asked
    #ownership#star

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