Open an editor and run code. JavaScript, TypeScript, React, React Native, HTML, and an API client. Nothing to install, and no account.
For interviews A strong tool for companies running live coding interviews.
Each one opens in the browser. Your work stays in this browser unless you copy it out.
Write JavaScript with syntax highlighting, auto-complete, and a live console. Supports ES2024 out of the box. Perfect for scripts, algorithms, and exploring APIs.
Like Jupyter — but for JavaScript. Run code cells one at a time, see output inline, and build up concepts step by step. Great for tutorials and experiments.
Write React components across files, import them, and run a live preview next to the code.
Write React Native components and see them on a phone preview. You can add files and import them the same way you would in a small app.
Write TypeScript and see it transpiled in real time. Understand type errors, interfaces, generics, and why TypeScript makes large codebases sane.
A full HTML/CSS/JS playground with a live preview pane. Build mini UIs, test DOM manipulation, or prototype a landing page concept instantly.
Send GET, POST, and the other methods. Save requests, switch environments, and attach a bearer token. Project APIs work when you run the local server.
Answer JavaScript questions and check what you know. Useful when you are preparing for an interview.
The editors are free to use. If one of them saved you time, a coffee helps pay for keeping the site up.
Opens Buy Me a Coffee in a new tab. You choose the amount there.
// Variables, functions & closures const greet = (name) => { const hour = new Date().getHours(); const time = hour < 12 ? 'morning' : hour < 18 ? 'afternoon' : 'evening'; return `Good ${time}, ${name}!`; }; // Destructuring + default params const profile = ({ name = 'stranger', age }) => `${name} is ${age} years old`; console.log(greet('Ayesha')); console.log(profile({ name: 'Rohan', age: 24 }));
// Async/await with error handling const fetchUser = async (id) => { try { const res = await fetch( `https://api.example.com/users/${id}` ); if (!res.ok) throw new Error('Not found'); const { name, email } = await res.json(); return { name, email }; } catch (err) { console.error(`Error: ${err.message}`); } }; // Promise.all — run in parallel const users = await Promise.all( [1, 2, 3].map(fetchUser) );
// Array methods — map, filter, reduce const products = [ { name: 'Laptop', price: 999, inStock: true }, { name: 'Mouse', price: 49, inStock: false }, { name: 'Desk', price: 349, inStock: true }, ]; const total = products .filter(p => p.inStock) .map(p => p.price) .reduce((sum, p) => sum + p, 0); console.log(`Total: $${total}`); // Optional chaining + nullish coalescing const first = products[0]?.name ?? 'Unknown';