TOAST UI Editor is an open-source Markdown editor developed by NHN, a major Korean technology company, that provides both Markdown and WYSIWYG editing modes with real-time preview synchronization. The editor follows CommonMark and GitHub Flavored Markdown specifications, ensuring documents render consistently across platforms. Users can switch between raw Markdown editing with syntax highlighting and a rich-text WYSIWYG mode that provides familiar word-processor-style formatting controls.
The editor is built with a modular plugin system that extends its capabilities well beyond basic Markdown. Official plugins add table cell merging, code syntax highlighting via Prism.js, color text formatting with an integrated color picker, and UML diagram rendering directly within the editor. Chart blocks allow embedding data visualizations, and the viewer component enables read-only rendering of Markdown content for documentation and content display scenarios.
TOAST UI Editor has accumulated over 17,000 GitHub stars and broad adoption in both Korean and international web development communities. The project provides official framework integrations for React and Vue alongside the vanilla JavaScript API, supports over 20 languages through its internationalization system, and offers extensive toolbar customization. Its lightweight footprint and clean API make it a popular choice for CMS builders, documentation platforms, and content creation tools.
