A browser based code editor
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Monaco Editor

Demo page

The Monaco Editor is the code editor that powers VS Code, a good page describing the code editor's features is here.


Try it out

See the editor in action here.

Learn how to extend the editor and try out your own customizations in the playground.

Browse the latest editor API at monaco.d.ts.


Please mention the version of the editor when creating issues and the browser you're having trouble in.

This repository contains only the scripts to glue things together, please create issues against the actual repositories where the source code lives:

  • monaco-editor-core -- (the editor itself)
  • monaco-typescript -- (JavaScript or TypeScript language support)
  • monaco-css -- (CSS, LESS or SCSS advanced language support)
  • monaco-json -- (JSON advanced language support)
  • monaco-languages -- (bat, coffee script, cpp, csharp, fsharp, go, ini, jade, lua, objective-c, powershell, python, r, ruby, sql, swift, vb or xml colorizers)

Known issues

In IE, the editor must be completely surrounded in the body element, otherwise the hit testing we do for mouse operations does not work. You can inspect this using F12 and clicking on the body element and confirm that visually it surrounds the editor.


npm install monaco-editor

You will get:

  • inside dev: bundled, not minified
  • inside min: bundled, and minified
  • inside min-maps: source maps for min
  • monaco.d.ts: this specifies the API of the editor (this is what is actually versioned, everything else is considered private and might break with any release).

It is recommended to develop against the dev version, and in production to use the min version.


Here is the most basic HTML page that embeds the editor. More samples are available at monaco-editor-samples.

<!DOCTYPE html>
	<meta http-equiv="X-UA-Compatible" content="IE=edge" />
	<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >

<div id="container" style="width:800px;height:600px;border:1px solid grey"></div>

<script src="monaco-editor/min/vs/loader.js"></script>
	require.config({ paths: { 'vs': 'monaco-editor/min/vs' }});
	require(['vs/editor/editor.main'], function() {
		var editor = monaco.editor.create(document.getElementById('container'), {
			value: [
				'function x() {',
				'\tconsole.log("Hello world!");',
			language: 'javascript'

Integrate cross domain

If you are hosting your .js on a different domain (e.g. on a CDN) than the HTML, you should know that the Monaco Editor creates web workers for smart language features. Cross-domain web workers are not allowed, but here is how you can proxy their loading and get them to work:

	Assuming the HTML lives on www.mydomain.com and that the editor is hosted on www.mycdn.com
<script type="text/javascript" src="http://www.mycdn.com/monaco-editor/min/vs/loader.js"></script>
	require.config({ paths: { 'vs': 'http://www.mycdn.com/monaco-editor/min/vs' }});

	// Before loading vs/editor/editor.main, define a global MonacoEnvironment that overwrites
	// the default worker url location (used when creating WebWorkers). The problem here is that
	// HTML5 does not allow cross-domain web workers, so we need to proxy the instantion of
	// a web worker through a same-domain script
	window.MonacoEnvironment = {
		getWorkerUrl: function(workerId, label) {
			return 'monaco-editor-worker-loader-proxy.js';

	require(["vs/editor/editor.main"], function () {
		// ...

	Create http://www.mydomain.com/monaco-editor-worker-loader-proxy.js with the following content:
		self.MonacoEnvironment = {
			baseUrl: 'http://www.mycdn.com/monaco-editor/min/'
	That's it. You're good to go! :)

More documentation

Find full HTML samples here.

Create a Monarch tokenizer here. image


Q: What is the relationship between VS Code and the Monaco Editor?
A: The Monaco Editor is generated straight from VS Code's sources with some shims around services the code needs to make it run in a web browser outside of its home.

Q: What is the relationship between VS Code's version and the Monaco Editor's version?
A: None. The Monaco Editor is a library and it reflects directly the source code.

Q: I've written an extension for VS Code, will it work on the Monaco Editor in a browser?
A: No.

Q: Why all these web workers and why should I care?
A: Language services create web workers to compute heavy stuff outside the UI thread. They cost hardly anything in terms of resource overhead and you shouldn't worry too much about them, as long as you get them to work (see above the cross-domain case).

Q: What is this loader.js? Can I use require.js?
A: It is an AMD loader that we use in VS Code. Yes.

Q: I see the warning "Could not create web worker". What should I do?
A: HTML5 does not allow pages loaded on file:// to create web workers. Please load the editor with a web server on http:// or https:// schemes. Please also see the cross domain case above.


Cheat Sheet

Running monaco-editor-core from source

Running a plugin (e.g. monaco-typescript) from source

Shipping a new monaco-editor version

Ship a new monaco-editor-core version (if necessary)

Adopt new monaco-editor-core in plugins (if necessary)

Adopt new monaco-editor-core

  • edit $/src/monaco-editor/package.json and update the version for (as necessary):
  • monaco-editor-core
  • monaco-typescript
  • monaco-css
  • monaco-json
  • monaco-languages
  • update the version in $/src/monaco-editor/package.json
  • I try to keep it similar to monaco-editor-core, maybe just vary the patch version.
  • fetch latest deps by running $/src/monaco-editor> npm install .

Package monaco-editor

  • run $/src/monaco-editor> npm run release

Try out packaged bits

Publish packaged bits

  • run $/src/monaco-editor/release> npm publish

Running the website from its source

Generating the playground samples

  • edit $/src/monaco-editor/website/playground/playground.mdoc
  • run $/src/monaco-editor> gulp playground-samples

Publishing the website

  • run $/src/monaco-editor> npm run website
  • force-push the gh-pages branch: $/src/monaco-editor-website> git push origin gh-pages --force

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.