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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

Staff+ Frontend at Datadog

FrontendStaff+No offer◆ Commonly asked· 2024

Staff frontend interview. Fundamentals mattered as much as getting to an answer.

The loop · 5 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Number of islands in a 2D grid.
    Staff+Medium◆ Commonly asked
    #bfs#dfs#grid
    PracticeLeetCode↗GeeksforGeeks↗
  • Same tree.
    Staff+Easy◆ Commonly asked
    #tree
    PracticeLeetCode↗GeeksforGeeks↗
  • Longest increasing subsequence.
    Staff+Hard◆ Commonly asked
    #dp#binary-search
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 1 question

Low-Level Design

Object-oriented / low-level design of a focused module.

  • Design a data-fetching cache with invalidation.
    Staff+Hard◆ Commonly asked
    #cache#oop
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a URL shortener like TinyURL.
    Staff+Medium◆ Commonly asked
    #hashing#cache#sharding
    PracticeGeeksforGeeks↗Search↗
  • Design a component/design-system architecture for many teams.
    Staff+Medium◆ Commonly asked
    #frontend#design-system
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 1 question

Hiring Manager

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

  • What is the biggest system you have designed, and why those choices?
    Staff+◆ Commonly asked
    #architecture
05

Round 05 · 2 questions

Behavioral / HR

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

  • How do you handle being blocked for several days?
    Staff+◆ Commonly asked
    #ownership#star
  • Describe a goal you set and how you achieved it.
    Staff+◆ 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.