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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

← Mercor

Senior Full-stack at Mercor

Full-stackSeniorRejected◆ Commonly asked· 2024

A senior fullstack loop. Coding-heavy early, design and behavioral later.

The loop · 6 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Serialize and deserialize a binary tree.
    SeniorHard◆ Commonly asked
    #tree#dfs
    PracticeLeetCode↗GeeksforGeeks↗
  • Two Sum — return indices of numbers adding to a target.
    SeniorEasy◆ Commonly asked
    #array#hashmap
    PracticeLeetCode↗GeeksforGeeks↗
  • Sort colors.
    SeniorMedium◆ Commonly asked
    #two-pointers#array
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a "Wordle" clone with keyboard input.
    SeniorMedium◆ Commonly asked
    #react#state
    PracticeGeeksforGeeks↗Search↗
  • Build a stopwatch with lap times.
    SeniorEasy◆ Commonly asked
    #react#state
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a ticket booking system (inventory + concurrency).
    SeniorHard◆ Commonly asked
    #concurrency#transactions
    PracticeGeeksforGeeks↗Search↗
  • Design a Google Docs-style collaborative editor (frontend).
    SeniorHard◆ Commonly asked
    #frontend#crdt#realtime
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Difference between controlled and uncontrolled inputs.
    SeniorEasy◆ Commonly asked
    #react#forms
    PracticeGeeksforGeeks↗Search↗
  • How do you implement dark mode without a flash?
    SeniorMedium◆ Commonly asked
    #css#ssr
    PracticeGeeksforGeeks↗Search↗
  • What is a deadlock and how do you avoid one?
    SeniorHard◆ Commonly asked
    #concurrency
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

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

  • How do you give difficult feedback to a peer?
    Senior◆ Commonly asked
    #leadership
06

Round 06 · 2 questions

Behavioral / HR

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

  • When did you change your mind after seeing new evidence?
    Senior◆ Commonly asked
    #judgment#star
  • Describe a disagreement on a code review and how it ended.
    Senior◆ Commonly asked
    #conflict#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.