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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

Mid Full-stack at Datadog

Full-stackMidOutcome unknown◆ Commonly asked· 2025

A mid fullstack loop. Balanced across coding, design, and collaboration.

The loop · 5 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Merge two sorted linked lists.
    MidEasy◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
  • Two Sum — return indices of numbers adding to a target.
    MidEasy◆ Commonly asked
    #array#hashmap
    PracticeLeetCode↗GeeksforGeeks↗
  • Reverse nodes in k-group.
    MidHard◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a key-value store with TTL expiry.
    MidMedium◆ Commonly asked
    #cache#ttl
    PracticeGeeksforGeeks↗Search↗
  • Build a tic-tac-toe game with win detection.
    MidEasy◆ Commonly asked
    #react#state
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 1 question

Low-Level Design

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

  • Design classes for a parking lot.
    MidMedium◆ Commonly asked
    #oop#design-patterns
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Idempotency in APIs — why and how.
    MidMedium◆ Commonly asked
    #api-design#idempotency
    PracticeGeeksforGeeks↗Search↗
  • Explain leader election and consensus (Raft) at a high level.
    MidHard◆ Commonly asked
    #distributed#consensus
    PracticeGeeksforGeeks↗Search↗
  • How do CSS specificity and the cascade resolve conflicts?
    MidMedium◆ Commonly asked
    #css
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 2 questions

Behavioral / HR

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

  • Tell me about a time you had to learn something quickly.
    Mid◆ Commonly asked
    #learning#star
  • A time you influenced a decision without authority.
    Mid◆ Commonly asked
    #influence#star

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