Markdown Preview Editor

A self-hosted Markdown editor and live previewer where your documents never leave the browser.

Try it online →

A static website you host yourself. Everything is processed locally in the browser: there is no backend, no analytics and no CDN. A strict Content-Security-Policy forbids the page from sending data anywhere.

Features

• Live preview with synchronized scrolling, light and dark themes, mobile layout.
• GitHub-flavored Markdown, code highlighting, math (KaTeX) and diagrams (Mermaid).
• Tabs: work with several documents at once, each with its own undo history; links between open .md files switch tabs.
• Drag & drop onto the editor: several files, whole folders, images dropped together with a document.
• Formatting toolbar with a collapsible Advanced editor row.
• Save as .md, export to self-contained HTML, print or save as PDF.
• 15 interface languages, picked from your browser settings and switchable in Settings: English, Deutsch, Español, Français, Italiano, Português, Nederlands, Svenska, Polski, Українська, Русский, Türkçe, 日本語, 한국어, 简体中文. Each language loads only when it is used.

Accessibility

The editor and its website meet WCAG 2.2 AA with zero violations reported by axe-core. The check runs as part of the test suite (tests/e2e/a11y.spec.ts) in the light and dark themes, including the preview, open panels and the phone layout; tabs, the pane divider and menus work from the keyboard. Run it yourself with npm run test:e2e (or against a live site: PW_BASE_URL=https://app.mdprevieweditor.com npm run test:e2e).

Privacy & safety

• The rendered document is shown in a sandboxed frame where scripts cannot run, and it is sanitized with DOMPurify.
• Full protection is on by default: external images, media and links are not loaded or followed. You can allow them one by one.
• Allowed links and media go through a lightweight offline check that flags phishing tricks, look-alike domains, executables and local-network addresses. It is a set of heuristics, not an antivirus.

Installation

Quickest way: download the ready-made site archive — markdown-preview-editor-site.zip (also available as .tar.gz) — extract it on your hosting, and the site works. No build step needed.

Or build it yourself with npm ci && npm run build, then choose how to serve it:

• Your website — extract release/markdown-preview-editor-site.tar.gz (or .zip) into your site's folder on any static hosting. The included .htaccess enables HTTPS and security headers on Apache/LiteSpeed.
• Docker — PORT=8080 docker compose -f deploy/docker-compose.yml up -d --build (pick any free port), then open http://localhost:PORT.
• nginx — copy dist/ to the web root and use deploy/nginx.conf.
• Caddy — copy dist/ to /srv and run SITE_ADDRESS=your.domain caddy run --config deploy/Caddyfile.
• Locally — npm run dev and open the printed address.

Links

License

MIT