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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

← Jane Street

Senior Frontend at Jane Street

FrontendSeniorRejected◆ Commonly asked· 2025

6-round senior frontend 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.

  • Min cost to connect all points.
    SeniorMedium◆ Commonly asked
    #graph#mst
    PracticeLeetCode↗GeeksforGeeks↗
  • Implement a trie (prefix tree).
    SeniorMedium◆ Commonly asked
    #trie
    PracticeLeetCode↗GeeksforGeeks↗
  • Course Schedule II.
    SeniorMedium◆ Commonly asked
    #graph#topo-sort
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a debounced autocomplete/search box with keyboard nav.
    SeniorMedium◆ Commonly asked
    #react#debounce#a11y
    PracticeGeeksforGeeks↗Search↗
  • Build a to-do app with filters and localStorage persistence.
    SeniorEasy◆ Commonly asked
    #react#state
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design an offline-capable web app with sync.
    SeniorHard◆ Commonly asked
    #frontend#offline#sync
    PracticeGeeksforGeeks↗Search↗
  • Design a distributed cache.
    SeniorHard◆ Commonly asked
    #cache#consistency
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Difference between CSS Grid and Flexbox — when to use each.
    SeniorEasy◆ Commonly asked
    #css#layout
    PracticeGeeksforGeeks↗Search↗
  • Explain the JS event loop: microtasks vs macrotasks.
    SeniorMedium◆ Commonly asked
    #javascript#event-loop
    PracticeGeeksforGeeks↗Search↗
  • How does React batching and the render phase work?
    SeniorHard◆ Commonly asked
    #react
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

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

  • What does a great engineering culture look like to you?
    Senior◆ Commonly asked
    #values
06

Round 06 · 2 questions

Behavioral / HR

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

  • Tell me about a project you are most proud of.
    Senior◆ Commonly asked
    #star
  • Describe handling a tight deadline with competing priorities.
    Senior◆ Commonly asked
    #prioritization#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.