theloop
CompaniesRoundsQuestionsSearchProgress
theloop

Interview questions from top companies, mapped to the exact round they show up in. Prep for what you will actually face.

View source

Browse

CompaniesSearchAll rounds

Rounds

Online AssessmentDSA / CodingMachine CodingLow-Level Design

Contribute

Share an interviewReport an issueStar on GitHub

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

← Slack

Senior Backend at Slack

BackendSeniorRejected◆ Commonly asked· 2024

A senior backend loop. Balanced across coding, design, and collaboration.

The loop · 6 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Same tree.
    SeniorEasy◆ Commonly asked
    #tree
    PracticeLeetCode↗GeeksforGeeks↗
  • Find median from data stream.
    SeniorHard◆ Commonly asked
    #heap#design
    PracticeLeetCode↗GeeksforGeeks↗
  • Reverse a linked list.
    SeniorEasy◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a REST endpoint with pagination, filtering and sorting.
    SeniorMedium◆ Commonly asked
    #api#pagination
    PracticeGeeksforGeeks↗Search↗
  • Implement an idempotent "charge" endpoint.
    SeniorHard◆ Commonly asked
    #idempotency#payments
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a file-sharing service with permissions.
    SeniorMedium◆ Commonly asked
    #storage#acl
    PracticeGeeksforGeeks↗Search↗
  • Design a ride-sharing service like Uber.
    SeniorHard◆ Commonly asked
    #geospatial#matching
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • How do you design an idempotency-key system for payments?
    SeniorHard◆ Commonly asked
    #idempotency#payments
    PracticeGeeksforGeeks↗Search↗
  • Explain the difference between horizontal and vertical scaling.
    SeniorEasy◆ Commonly asked
    #scale
    PracticeGeeksforGeeks↗Search↗
  • Explain eventual consistency with a real example.
    SeniorHard◆ Commonly asked
    #distributed
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

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

  • Where do you want to grow in the next two years?
    Senior◆ Commonly asked
    #growth
06

Round 06 · 2 questions

Behavioral / HR

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

  • Describe a goal you set and how you achieved it.
    Senior◆ Commonly asked
    #ownership#star
  • When did you take ownership of something outside your scope?
    Senior◆ 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.