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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

← Discord

Mid Backend at Discord

BackendMidOffer◆ Commonly asked· 2025

5-round mid backend process. Coding-heavy early, design and behavioral later.

The loop · 5 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Decode ways.
    MidMedium◆ Commonly asked
    #dp#string
    PracticeLeetCode↗GeeksforGeeks↗
  • Longest palindromic substring.
    MidMedium◆ Commonly asked
    #string#dp
    PracticeLeetCode↗GeeksforGeeks↗
  • Kth smallest element in a BST.
    MidMedium◆ Commonly asked
    #tree#bst
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Parse and evaluate a simple expression/DSL.
    MidMedium◆ Commonly asked
    #parsing
    PracticeGeeksforGeeks↗Search↗
  • Implement an LRU + TTL cache library.
    MidHard◆ Commonly asked
    #cache#ttl
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 1 question

Low-Level Design

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

  • Design a chess game (pieces, moves, board).
    MidHard◆ Commonly asked
    #oop
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • Explain connection pooling and why it matters.
    MidMedium◆ Commonly asked
    #databases
    PracticeGeeksforGeeks↗Search↗
  • How would you design and version a public REST API?
    MidMedium◆ Commonly asked
    #api-design
    PracticeGeeksforGeeks↗Search↗
  • Explain database indexing and when a query uses one.
    MidMedium◆ Commonly asked
    #databases#indexing
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 2 questions

Behavioral / HR

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

  • A time you made a mistake in production — what happened next?
    Mid◆ Commonly asked
    #ownership#star
  • Describe a conflict with your manager and the outcome.
    Mid◆ Commonly asked
    #conflict#star

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