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Interviews
500+ questions asked at top tech companies. Write the code, see it render, compare with the solution.
Real interview questions from
Build components that render live
Star ratings, modals, carousels, data tables. Write React or vanilla JavaScript and see the result instantly.
Practice UI questionsHigh in fiber and vitamins.
High in fiber and vitamins.
High in fiber and vitamins.
Implement the core functions
Debounce, promises, polyfills, array utilities. Run your code and check it against the solution.
Practice JavaScriptfunction debounce(fn, wait) {
let timer;
return (...args) => {
clearTimeout(timer);
timer = setTimeout(fn, wait, ...args);
};
}
const save = debounce(write, 300);
save(); save(); save();Design frontend systems step by step
Break down news feeds, autocomplete, and chat apps. Then go deeper: monorepos, microfrontends, real-time transports, future-proof components.
Explore system designExplain how the browser works
Event loop, closures, rendering, networking. Direct answers you can repeat in an interview.
Browse conceptual questionsWhat happens when you type a URL?
Practice in a real editor.
Monaco, live tests, and console output. No local setup.
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Questions
500+ practice questions across UI, JS, and concepts.
System design
Question breakdowns and system design core concepts for senior roles.
Solutions
Expert solutions with best practices for every question.
Test cases
Evaluate your code against real test cases.
Evaluation
Interviewer evaluation criteria from top companies.