#react

21 react interview questions, asked at Stripe, xAI, Apple and 11 more companies. Last asked Sep 2026.

React social feed with voting, re-sorting and pinned postsCodingBuild a feed page in React. Each post can be upvoted or downvoted, and after every vote the feed re-sorts by score, highest first. A post can be pinned, and pinned posts stay at…
Last asked Sep 2026
Credit card form with validation and linked fieldsCodingBuild a card-details form in the browser (React is fine): cardholder name, card number, expiry date and security code. Validate each field as the user types and on submit, and…
Last asked Sep 2026
React typeahead with async suggestions and keyboard navigationCodingBuild a typeahead in React: a search input with a dropdown of suggestions that come from an asynchronous source while the user types. The user can pick a suggestion with the mouse…
Last asked Sep 2026
Render nested JSON in a code-style viewerCodingBuild a React component that displays a given JSON object the way a code editor would: indentation, braces and brackets, keys and values styled by type, and nested objects and…
Last asked Sep 2026
React list loaded with useEffectCodingWrite a React component that loads a list from an endpoint with useEffect and displays it. Handle loading and error states, keys for list items, and cleanup so a late response…
Last asked Sep 2026
Arrow-key controlled kanban board in ReactCodingBuild a kanban board in React with columns of cards. A card can be selected, and the arrow keys move the selection or the selected card between positions and columns. Keep the…
Last asked Aug 2026
Virtualized spreadsheet grid in React with cell formulasCodingBuild a spreadsheet in React. The grid is large, so render only the rows and columns in view and keep scrolling smooth. Cells can hold plain values or formulas that refer to other…
Last asked Jul 2026
Accessible expand-and-collapse tree in ReactCodingBuild a React component that renders nested data as a tree where each node can be expanded or collapsed, to any depth. Render it recursively, keep the expanded state sensibly, and…
Last asked Jul 2026
Build a React interface against an undocumented APICodingWith an AI coding assistant available, build a React interface on top of an API that has no documentation. Work out the endpoints and the shape of their data by exploring them…
Last asked Jun 2026
Parking lot manager in ReactCodingBuild a small React app that manages a parking lot: show the spots and whether each is free, let vehicles park and leave, and keep everything on screen in sync. The round focuses…
Last asked May 2026
Build a chat input that renders a streamed AI replyCodingBuild a minimal ChatGPT-like page: a text box and a submit button, and below them the model's reply, rendered as it streams back from the API rather than all at once. Handle the…
Last asked Apr 2026
React Battleship boardCodingIn React, build the board for the game Battleship (just the board, no opponent logic). Each cell can be clicked to change its state (empty, hit, miss), and the board shows which…
Last asked Apr 2026
React fundamentals and error handlingCodingExplain core React concepts: components and props, state and re-renders, hooks and their rules, effects and cleanup, keys in lists. Then explain how you handle errors in a React…
Last asked Feb 2026
React class components, lifecycle methods and hooksCodingExplain how React class components work and the order of their lifecycle methods (mount, update, unmount), then how the same behavior is written with hooks: useState, useEffect…
Last asked Jan 2026
React hook for API data and UI changes in a starter appCodingIn a starter React app with API and UI code already written: write a hook that fetches data from the API and converts it to the shape the UI needs, then change the UI as asked…
Last asked Sep 2025
Multi-step form in ReactCodingBuild a three-step form: step 1 collects the user's basic details, step 2 their address, and step 3 shows everything for confirmation and submits. Support validation on each step…
Last asked Sep 2025
Searchable transaction list that highlights the largestCodingBuild a small interface in three steps: 1. Render a list of transactions given as {name: string, amount: number}. 2. Highlight the name of the transaction with the largest amount…
Last asked Sep 2025
Build a booking widget with live pricingCodingBuild a small reservation widget for a listing, front end and a simple back end. Pick check-in and check-out dates and the number of adults and children; show the total price…
Last asked Aug 2025
Paginated, sortable React tableCodingBuild a React table component that takes its column definitions as data, sorts by a column when its header is clicked and pages through rows. Keep the component split and the…
Last asked Aug 2025
Find bugs and slow renders in a React appCodingYou get a small React codebase with several bugs and performance problems. Find and fix them: unnecessary re-renders, event listeners that are never cleaned up, and similar…
Last asked Aug 2025
Collapsible JSON viewer in ReactCodingIn an hour of React, pretty-print a JSON value (objects, arrays, strings, numbers) with indentation, and give every nested object and array a toggle that collapses it to a…
Last asked Jul 2025