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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

← Datadog

New Grad / Junior Frontend at Datadog

FrontendNew Grad / JuniorWithdrew◆ Commonly asked· 2025

5-round junior frontend process. Coding-heavy early, design and behavioral later.

The loop · 5 rounds

01

Round 01 · 1 question

Online Assessment

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

  • Validate an IP address (IPv4 / IPv6).
    New Grad / JuniorMedium◆ Commonly asked
    #string#parsing
    PracticeGeeksforGeeks↗Search↗
02

Round 02 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Set matrix zeroes.
    New Grad / JuniorMedium◆ Commonly asked
    #matrix
    PracticeLeetCode↗GeeksforGeeks↗
  • Subtree of another tree.
    New Grad / JuniorEasy◆ Commonly asked
    #tree#dfs
    PracticeLeetCode↗GeeksforGeeks↗
  • Clone a graph.
    New Grad / JuniorMedium◆ Commonly asked
    #graph#dfs
    PracticeLeetCode↗GeeksforGeeks↗
03

Round 03 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a debounced autocomplete/search box with keyboard nav.
    New Grad / JuniorMedium◆ Commonly asked
    #react#debounce#a11y
    PracticeGeeksforGeeks↗Search↗
  • Build a nested, collapsible comment thread.
    New Grad / JuniorMedium◆ Commonly asked
    #react#recursion
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Explain the JS event loop: microtasks vs macrotasks.
    New Grad / JuniorMedium◆ Commonly asked
    #javascript#event-loop
    PracticeGeeksforGeeks↗Search↗
  • How does React batching and the render phase work?
    New Grad / JuniorHard◆ Commonly asked
    #react
    PracticeGeeksforGeeks↗Search↗
  • Explain prototypal inheritance.
    New Grad / JuniorMedium◆ Commonly asked
    #javascript
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 2 questions

Behavioral / HR

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

  • Describe handling a tight deadline with competing priorities.
    New Grad / Junior◆ Commonly asked
    #prioritization#star
  • Describe working with an ambiguous or shifting requirement.
    New Grad / Junior◆ Commonly asked
    #ambiguity#star

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