Monaco Editor

Monaco Editor is the web-based code editor that powers Microsoft Visual Studio Code (VS Code), extracted as a standalone, embeddable JavaScript library for use in web applications. Developed by Microsoft and originally released in 2016 alongside the open-sourcing of VS Code, Monaco provides a full-featured code editing experience in the browser with capabilities including syntax highlighting for over 80 programming languages via Monarch tokenizer declarations, IntelliSense code completion with parameter hints and signature help, code folding, multi-cursor editing, bracket matching, auto-closing brackets and quotes, semantic token-based theming, find and replace with regular expressions, minimap, diff editor for side-by-side file comparison, inline hints, hover information, code lens, and diagnostic markers (squiggly underlines for errors and warnings). The editor supports both light and dark themes and is fully customizable through CSS and the theming API. Monaco's language services provide rich features like go-to-definition, find all references, rename refactoring, and document symbols for languages including TypeScript, JavaScript, CSS, LESS, SCSS, JSON, HTML, and Markdown out of the box. For other languages, language servers can be integrated via the Language Server Protocol (LSP). The editor is built in TypeScript using the same editor core as VS Code, ensuring consistent behavior and performance. Monaco is used by thousands of web applications and platforms including GitHub (for web-based code editing), GitLab, Azure DevOps, CodeSandbox, StackBlitz, Replit, Glitch, Chrome DevTools, TypeForm, and many IDE-in-browser products. With over 40,000 GitHub stars, Monaco is the de facto standard for embedding code editors in web applications.