JavaScript REPL

Type an expression, run it, read the result instantly.

A free online JavaScript REPL with an interactive console, npm packages, and live preview. Evaluate expressions, test a method, or check what a snippet returns - all in your browser, nothing to install. No signup required. Trusted by 1.1M+ developers.

Open REPL

No credit card required · Free to use

or download desktop client for

Mac Windows Linux

1.1M+

Users

2.7M+

Projects Created

2016

Since

TRUSTED BY

About this tool

One of Playcode's coding tools

This REPL is one of the coding tools Playcode supports, free in your browser. Playcode's main product today helps you build and run websites and apps with AI: describe what you need, and the agent builds it, publishes it, and changes it when you ask. What is Playcode

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Built for Everyone

Whether you're learning JavaScript or building production apps, this playground has you covered

For Beginners

Learn JavaScript without installing anything. Write code, see results instantly. Perfect JavaScript playground for beginners who want to start coding immediately.

No downloads, no configuration, no command line. This free JavaScript sandbox runs entirely in your browser. Follow along with tutorials and see your code execute in real-time. Perfect online JavaScript playground for learning to code.

✓Zero setup required - just open and code
✓Built-in tutorials for learning JavaScript
✓Instant feedback with live preview
✓Helpful error messages and debugging

Best for: Students, coding bootcamps, JavaScript learners, online courses

For Professionals

Prototype faster with AI-powered code generation. Import npm packages instantly, build with React/Vue/TypeScript, and publish to production with one click.

This online JavaScript playground gives you the power of a full IDE without the setup time. AI understands your project context and writes complete features, not just autocomplete suggestions. The best JS playground for rapid prototyping.

✓AI coding assistant writes working code
✓Access 2M+ npm packages instantly
✓TypeScript, JSX, and ES2026 support
✓One-click deployment to custom domains
✓Multi-file projects with hot reload

Best for: Senior developers, prototyping, MVPs, client demos, rapid testing

For Teams

Collaborate in real-time with your team. Conduct live coding interviews, pair program, or teach workshops. Multiple developers can edit the same JavaScript playground simultaneously.

This online code playground supports real-time collaboration out of the box. Share a URL and start coding together. Perfect for technical interviews, pair programming, and remote teams. The best JavaScript sandbox for collaborative coding.

✓Real-time collaborative editing
✓Live cursors and selections
✓Share via URL - no account required
✓Perfect for coding interviews
✓Team workspaces for organization

Best for: Technical interviews, pair programming, code reviews, teaching, remote teams

All JavaScript Frameworks Supported

Build with React, Vue, Angular, Svelte, TypeScript, or vanilla JavaScript. Style with Tailwind CSS, Bootstrap, or any CSS framework. Our JS playground comes pre-configured with all tooling.

React·Vue·Angular·TypeScript·Tailwind·HTML

Beyond JavaScript: Multi-Language Support

Playcode's coding tools started with a JavaScript playground and now cover Python, C++, C, Go, SQL, and more. Each compiler runs code directly in your browser with instant feedback.

Python Compiler·C++ Compiler·C Compiler·Go Compiler·JavaScript Compiler

Free Developer Tools

Beyond our JavaScript playground, we offer productivity tools for developers. All free, all in your browser. No signup required.

JSON Formatter·JSON Diff·JSON to TypeScript·Regex Tester·HTML Runner

New to JavaScript?

Start with these beginner-friendly tutorials

letVariables "A"Data Types fnFunctions +Operators >_Console { }Scope asyncAsync =>Types //Comments ( )Params

Get on Board

Quick Start from a Template. Start instantly using pre-made templates. Over 2 million NPM packages available from the start. React, Vue, Lodash, RxJs, p5.js, Three.js and more.

See Result as You Type. Experience the fastest coding experience ever with Playcode. Instantly observe the results as you type.

Debug in Console. Enhance your speed and debugging skills rapidly using Playcode's efficient platform.

Live collaboration is built-in. Conduct coding interviews or create together with others from anywhere in the world, on any device.

          
            // Task 1: Sum of All Elements in an Array
// Example:
console.log(sumArray([1, 2, 3, 4])); // 10

          
            // Hmm... Let me try
function sumArray(arr) {
    return arr.reduce((acc, curr) => acc + curr, 0);
}

// That's a really elegant solution!

Deploy and Share your Project. Make your projects live with just one click. With zero setup and custom domains, sharing your web apps with the world has never been simpler.

.playcode.io

Online Playgrounds & Compilers

Write, compile, and run code instantly in your browser. No setup required.

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Features

Code Autocomplete. Enhance your coding speed and efficiency with smart code autocomplete feature. Avoid checking the documentation frequently.

Bug Finder. Playcode can identify and display all errors, providing assistance to fix them. Write, run code, correct any errors quickly.

The Most Flexible Layout.

Arrange panels as you like.

Upload Assets. Images, videos, sounds, shaders and others.

Color Themes.

Feels great in any environment.

Ready to use
JavaScript Playground

No need to configure your own IDE preset, start immediately.

Open Playground

Code seamlessly from any device

Jumping from your Mac to your iPad to your iPhone is no problem. Web editor is optimized for all devices.

Frequently Asked Questions

Everything you need to know about the JavaScript REPL

What is a JavaScript REPL?

A REPL (Read-Eval-Print Loop) evaluates JavaScript one expression at a time and prints the result immediately. Playcode's JavaScript REPL is a free browser-based coding tool: type an expression, run it, and read the output in the console instantly - no Node install, no setup.

How is a REPL different from a full editor?

A REPL is built for quick, interactive evaluation - test an expression, check a method, confirm what a snippet returns. Playcode gives you that instant console feedback, and when a quick test grows into a project you get a full multi-file editor with live preview in the same tab.

Can I use npm packages in the REPL?

Yes. Import any of over 2 million npm packages by name and Playcode bundles them automatically, so you can try a library method and see its output in the console right away - no npm install needed.

Do I need to install Node or sign up?

No. The REPL runs in your browser - nothing to install, no signup to start. Create a free account only if you want to save sessions and reopen them across devices.

Does it support TypeScript?

Yes. Write TypeScript or JSX and Playcode compiles it on the fly, so you can evaluate typed expressions and component code interactively.

Can I share what I run in the REPL?

Every session gets a unique playcode.io URL. Share it and anyone can open your code, run it, and fork their own copy - handy for reproducing behavior or answering a question with a live example.

What our users value

No coding needed

Results in minutes

Works on phone

Built my landing page in 20 minutes.

I described what I wanted and watched it build in real-time. No coding, no templates, just conversation. The AI understood exactly what I meant. My landing page looks professional and I published it the same day. This is how website building should work.

- Sarah Mitchell

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