Monaco Editor

Browser-based code editor that shares the same engine as VS Code, providing a full IDE experience directly in web applications. Ships IntelliSense, syntax highlighting, validation, and a diff editor for supported languages including JavaScript, TypeScript, JSON, CSS, and HTML.

Monaco is built straight from VS Code sources with shims for the browser environment. It stands apart from alternatives like CodeMirror or Ace by offering near-parity with VS Code editing features, including multi-file models, custom completion providers, and integration with Language Server Protocol when the server runs in JavaScript. MIT licensed, runs on major desktop browsers but not on mobile.

Key features:

• IntelliSense, validation, and hover information out of the box for supported languages
• Side-by-side diff editor with live comparison across all supported languages
• Model-based architecture with URIs, enabling virtual file systems and multi-file editing
• Custom providers for completion and hover, compatible with LSP-based tooling in JS
• Monarch tokenizer support for defining new language grammars
• ESM and legacy AMD builds, with samples for webpack integration

Common uses include web IDEs, code playgrounds, documentation sites with editable examples, and admin panels for editing JSON or YAML config. Developers integrate it for in-browser SQL or query builders, low-code editors that expose a code view, and notebook-style interfaces where code and output are edited side by side.