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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.

CC BY-NC 4.0 · © 2026

← Fastly

Senior Frontend at Fastly

FrontendSeniorOffer◆ Commonly asked· 2023

6-round senior frontend process. Fundamentals mattered as much as getting to an answer.

The loop · 6 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Daily temperatures.
    SeniorMedium◆ Commonly asked
    #stack#monotonic-stack
    PracticeLeetCode↗GeeksforGeeks↗
  • Group anagrams from a list of strings.
    SeniorMedium◆ Commonly asked
    #hashmap#string
    PracticeLeetCode↗GeeksforGeeks↗
  • Reverse nodes in k-group.
    SeniorHard◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 2 questions

Machine Coding

Build a working component or service under time pressure.

  • Build a debounced autocomplete/search box with keyboard nav.
    SeniorMedium◆ Commonly asked
    #react#debounce#a11y
    PracticeGeeksforGeeks↗Search↗
  • Build a "Wordle" clone with keyboard input.
    SeniorMedium◆ Commonly asked
    #react#state
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a Google Docs-style collaborative editor (frontend).
    SeniorHard◆ Commonly asked
    #frontend#crdt#realtime
    PracticeGeeksforGeeks↗Search↗
  • Design a large dashboard with many live widgets.
    SeniorHard◆ Commonly asked
    #frontend#realtime#perf
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 3 questions

Tech Deep-Dive

Deep questions on your core stack and fundamentals.

  • What is the difference between var, let and const?
    SeniorEasy◆ Commonly asked
    #javascript
    PracticeGeeksforGeeks↗Search↗
  • Explain Core Web Vitals (LCP, CLS, INP) and how to improve them.
    SeniorHard◆ Commonly asked
    #perf
    PracticeGeeksforGeeks↗Search↗
  • What are Web Workers and when would you use one?
    SeniorMedium◆ Commonly asked
    #browser#perf
    PracticeGeeksforGeeks↗Search↗
05

Round 05 · 1 question

Hiring Manager

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

  • How do you set technical direction for a team?
    Senior◆ Commonly asked
    #leadership#strategy
06

Round 06 · 2 questions

Behavioral / HR

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

  • Tell me about the most impactful project of your career.
    Senior◆ Commonly asked
    #impact#star
  • Describe a goal you set and how you achieved it.
    Senior◆ Commonly asked
    #ownership#star

Practice each round across every company

  • DSA / Coding
  • Machine Coding
  • System Design
  • Tech Deep-Dive
  • Hiring Manager
  • Behavioral / HR

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