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Frontend Engineer Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
- 9403
- Questions
- 546
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- 11
- Topics
- 8
- Languages
Showing 1–30 of 93 results
- AirwallexMediumFrontend EngineerDesign a Reusable React Autocomplete Input: API, Portals, Debounce and Caching
Design a reusable autocomplete search input for a React application on top of an existing search API. The discussion covers the API contract with pagination and limits, the component and portal architecture, throttling versus debouncing, client-side result caching strategies, and the public props and exports.
System DesignTechnical Screen - AirwallexMediumFrontend EngineerName-Keyed Async Task Scheduler with Sequential Lanes, Cancel and Clear by Name
Implement a JavaScript task scheduler for async functions where tasks sharing a name run strictly in order while tasks with different names run concurrently. Follow-ups add cancelling the running task for a name and clearing every running and queued task by name, testing promise handling, race conditions and API design.
Software Engineering FundamentalsTechnical Screen - AmazonMediumFrontend EngineerBuild Accessible Data-Loading Popovers for Multiple Buttons
This problem tests the ability to build a robust, accessible UI component that manages asynchronous data fetching, state synchronization, and DOM-level focus management.
Software Engineering FundamentalsOnsiteFrontendReactAccessibility - AmazonMediumFrontend EngineerDesign a Debounced Product Search Box
Design and implement an accessible, resilient product search-as-you-type component featuring debounced requests, race-condition handling via request cancellation, client-side caching, and keyboard navigation.
Software Engineering FundamentalsOnsitefrontendjavascriptreact - AmazonMediumFrontend EngineerDrive an Improvement Beyond Your Formal Responsibilities
This question assesses a candidate's ability to proactively identify technical or operational inefficiencies, influence stakeholders without formal authority, and implement measurable, sustainable improvements.
Behavioral & LeadershipOnsiteLeadershipInitiativeCollaboration - AmazonMediumFrontend EngineerFormat a Forest of Nested Comments
This problem tests your ability to reconstruct hierarchical relationships from flat input data and format them into a visual tree representation with specific character-based connectors.
Coding & AlgorithmsOnsiteRecursionTree TraversalString Formatting - AmazonMediumFrontend EngineerImplement an Accessible Autocomplete Search Component
Design and implement an accessible, race-condition-resilient autocomplete search component in React or modern JavaScript, focusing on debounced queries, ARIA combobox semantics, and keyboard navigation.
Software Engineering FundamentalsTechnical ScreenReactAccessibilityFrontend - AmazonMediumFrontend EngineerIntervene When Your Team Is Heading in the Wrong Direction
This question assesses a candidate's ability to identify technical or strategic misalignments within a project and their skill in providing constructive, data-driven feedback while maintaining team cohesion.
Behavioral & LeadershipOnsiteLeadershipCommunicationConflict Resolution - AmazonMediumFrontend EngineerInvestigate a Difficult Problem Until You Found the Root Cause
This question assesses the candidate's ability to systematically troubleshoot complex technical issues, demonstrate technical ownership, and implement long-term solutions rather than quick fixes.
Behavioral & LeadershipOnsiteBehavioralOwnershipDebugging - AmazonMediumFrontend EngineerLearn and Apply a Front-End Technology Across Devices
This question assesses a candidate's ability to self-teach new technologies and integrate them into a production environment while accounting for cross-platform performance and accessibility constraints.
Behavioral & LeadershipOnsiteBehavioralFrontendSelf-Learning - AmazonMediumFrontend EngineerMaximize the number of binary strings chosen under zero and one budgets
Given a list of binary strings and separate limits on the total number of zeros and ones, find the largest number of strings that can be chosen together without exceeding either limit. Tests optimization under two simultaneous resource limits, moving from brute force to an efficient method, and complexity analysis.
Coding & AlgorithmsTechnical Screen - AmazonMediumFrontend EngineerNavigate a Tight Deadline and an Ambiguous Engineering Project
This question assesses a candidate's ability to maintain engineering standards and project momentum when facing high-pressure timelines and limited requirements.
Behavioral & LeadershipTechnical ScreenBehavioralProject ManagementPrioritization - AmazonMediumFrontend EngineerOwn a Mistake with Real Consequences
This question assesses the candidate's integrity, ownership, and ability to implement systemic improvements following a significant professional error.
Behavioral & LeadershipOnsiteBehavioralOwnershipLeadership - AmazonMediumFrontend EngineerPredict JavaScript let and var Behavior
Tests deep understanding of JavaScript variable declarations (var vs let), focusing on hoisting, the Temporal Dead Zone (TDZ), block vs function scoping, and per-iteration lexical bindings in asynchronous loops.
Software Engineering FundamentalsOnsitejavascriptclosureshoisting - AndurilMediumFrontend EngineerDiagnose a Memory Leak in a JavaScript Web Application
Tests your ability to identify common JavaScript memory leak patterns—such as detached DOM trees, uncleared event subscriptions, and unbounded closures—and verify resolution using browser heap profiling techniques.
Software Engineering FundamentalsOnsiteJavaScriptPerformanceMemory Management - AppleMediumFrontend EngineerBuild an Accessible Recursive Expand-and-Collapse Tree in React
This problem tests recursive component design in React, state management for nested data structures, and the implementation of WAI-ARIA standards for accessible UI components.
Software Engineering FundamentalsTechnical ScreenReactFrontendAccessibility - AppleMediumFrontend EngineerDiagnose Cold-Load and Massive-Table Performance in a Web App
This problem tests your understanding of critical path rendering optimization for cold loads and memory management strategies for handling massive datasets in a browser environment.
Software Engineering FundamentalsTechnical ScreenPerformanceDOMReact - AppleMediumFrontend EngineerExplain JavaScript Scope, Closures, Timers, and the Event Loop
Tests deep understanding of the JavaScript runtime, specifically lexical scope, closures, the distinction between task and microtask queues in the event loop, and browser script loading mechanics.
Software Engineering FundamentalsTechnical ScreenJavaScriptEvent LoopClosures - AtlassianHardFrontend EngineerBuild a 2x3 React Feed Grid from Static Data, Then from an API, and Explain Your Hooks
A front-end coding exercise: show feed items with an id, text and creation time in a two-row, three-column React grid, first from static data and then from a provided API. It tests CSS grid layout, data fetching with loading and error states, effect cleanup, and how clearly the candidate explains the React hooks they use.
Software Engineering FundamentalsTechnical Screen - AtlassianMediumFrontend EngineerBuild a Social Feed List in HTML/CSS, Then Render It from a Mock API
A two-stage front-end coding exercise: build a Twitter-style social feed list with HTML and CSS, then render it from a mock API. It tests semantic markup, a resilient card layout, asynchronous loading with loading and error states, and safe rendering of user-generated text.
Software Engineering FundamentalsTechnical Screen - AtlassianHardFrontend EngineerDesign a Fast Product Search Page: Search Input over an Unbounded Catalog Grid
A front-end system design question about a product search page with a search input above a grid of results drawn from a catalog of unbounded size. It probes the component tree, where search state should live, and how the candidate keeps typing responsive and results fast when the result set can never be loaded all at once.
System DesignTechnical Screen - AtlassianMediumFrontend EngineerFront-End Design of an Emoji Picker with a Search Field
A candidate-driven front-end system design discussion about an emoji picker with a search field. It tests how a candidate scopes the component, models and loads the emoji catalog, ranks search results, keeps a grid of thousands of emoji fast, and supports keyboard and screen-reader users.
System DesignTechnical Screen - CensysMediumFrontend EngineerAdd Case-Insensitive Search to a Support Ticket Queue UI and Debug Its Behavior
A frontend exercise on an existing support ticket queue with Unresolved and Archived tabs, a ticket list and an activity panel: make the search box filter tickets by title or assignee regardless of letter case, then debug parts of the app that misbehave. It tests reading unfamiliar code, state design and systematic debugging.
Software Engineering FundamentalsTechnical Screen - CitadelEasyFrontend EngineerBuild a Real-Time Event Feed Dashboard
Implement a robust React hook to manage a high-frequency, real-time event feed dashboard with pause/resume controls, out-of-order de-duplication, memory bounding, and rolling time-window statistics.
Software Engineering FundamentalsTechnical Screenreacttypescriptsliding-window - CohereMediumFrontend EngineerBuild a Credit Card Form With Validation and Linked Input Fields
A front-end UI coding question: build a credit card form with card number, name, expiry and security code, where every field is validated and the fields are linked, so the detected card network changes formatting and security-code rules. It tests state design, caret-safe input formatting, error timing, accessibility and safe handling of card data.
Software Engineering FundamentalsOnsite - CohereMediumFrontend EngineerDesign Real-Time Comments with Optimistic Updates
Design optimistic real-time comments with temporary identities, idempotent posting, response/event reconciliation, visible failure states, and durable history.
System DesignOther - CohereMediumFrontend EngineerDesign a Real-Time Comment System Front End With Optimistic Updates
Front-end system design for a real-time comment feed, centered on optimistic updates: a new comment is appended to the list before the backend confirms it, so the user can keep typing. It tests client state modeling, reconciliation with live echoes, failure and retry handling, ordering, reconnection and rendering performance.
System DesignOnsite - CoinbaseHardFrontend EngineerDesign Frontend Architecture for Trading UI
This question evaluates competency in frontend architecture for real-time trading UIs, covering state management, rendering strategies, real-time data flow, performance, reliability, security, testing, and observability.
System DesignOnsite - CoinbaseHardFrontend EngineerImplement a Reusable Dropdown Component
This question evaluates skills in reusable frontend component design, including API design, state management (controlled vs uncontrolled), event handling, keyboard navigation, and accessibility (roles, focus behavior, and ARIA) for production-ready UI components.
Software Engineering FundamentalsOnsite - CoinbaseHardFrontend EngineerPresent a Previous Project Deep Dive
This question evaluates technical depth, architectural reasoning, leadership, and cross-team collaboration skills within frontend engineering, focusing on system/frontend architecture, tradeoff analysis, incident management, and measurable impact.
Behavioral & LeadershipOnsite
Airwallex
Amazon
Apple
Atlassian
Citadel
Cohere
Coinbase