theloop
CompaniesRoundsQuestionsSearchProgress
theloop

Interview questions from top companies, mapped to the exact round they show up in. Prep for what you will actually face.

View source

Browse

CompaniesSearchAll rounds

Rounds

Online AssessmentDSA / CodingMachine CodingLow-Level Design

Contribute

Share an interviewReport an issueStar on GitHub

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

← Cockroach Labs

New Grad / Junior Frontend at Cockroach Labs

FrontendNew Grad / JuniorRejected◆ Commonly asked· 2025

A junior frontend loop. 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.

  • Compute the running median of a stream.
    New Grad / JuniorHard◆ Commonly asked
    #heap
    PracticeGeeksforGeeks↗Search↗
02

Round 02 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Subtree of another tree.
    New Grad / JuniorEasy◆ Commonly asked
    #tree#dfs
    PracticeLeetCode↗GeeksforGeeks↗
  • Valid Parentheses — check balanced brackets.
    New Grad / JuniorEasy◆ Commonly asked
    #stack#string
    PracticeLeetCode↗GeeksforGeeks↗
  • Two Sum — return indices of numbers adding to a target.
    New Grad / JuniorEasy◆ Commonly asked
    #array#hashmap
    PracticeLeetCode↗GeeksforGeeks↗
03

Round 03 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a nested, collapsible comment thread.
    New Grad / JuniorMedium◆ Commonly asked
    #react#recursion
    PracticeGeeksforGeeks↗Search↗
  • Build an image carousel with autoplay and swipe.
    New Grad / JuniorMedium◆ Commonly asked
    #react#ui
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • What is the virtual DOM and why does it help?
    New Grad / JuniorMedium◆ Commonly asked
    #react
    PracticeGeeksforGeeks↗Search↗
  • How does a service worker enable offline support?
    New Grad / JuniorMedium◆ Commonly asked
    #pwa#offline
    PracticeGeeksforGeeks↗Search↗
  • Explain hydration and the cost of client vs server rendering.
    New Grad / JuniorHard◆ Commonly asked
    #ssr#perf
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 2 questions

Behavioral / HR

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

  • Describe a time you improved a process or tool for your team.
    New Grad / Junior◆ Commonly asked
    #ownership#star
  • Tell me about receiving hard feedback and acting on it.
    New Grad / Junior◆ Commonly asked
    #feedback#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.