MDBuild.io — Free Markdown Editor with Live Preview, Mermaid Diagrams, KaTeX Math & Export

MDBuild is a free, private, browser-based markdown editor for writers and developers. Write GitHub-flavored Markdown with live preview, GitHub Alerts, Mermaid diagrams, KaTeX math equations, interactive task lists, footnotes, and syntax-highlighted code blocks. Export to PDF, HTML, DOCX, and PNG. Works offline as a Progressive Web App — no sign-up, no server, no tracking. Your documents stay in your browser.

Features

• Live markdown preview with GitHub-flavored syntax
• Mermaid diagrams, KaTeX math, syntax highlighting
• GitHub Alerts, callouts, admonitions, footnotes
• Interactive task lists with keyboard shortcuts
• Export to PDF, HTML, DOCX, PNG
• Installable PWA — works offline
• 100% client-side — private by default

Open the editor to start writing, or read the help guide.