CodeInk is a free, open-source online Markdown editor with a clean, professional UI. Real-time preview, Mermaid diagrams, KaTeX math, syntax highlighting, and markdown linting. 100% client-side — your documents never leave your browser.

Get Started   ✦   Markdown Cheat Sheet   ✦   License

Features

• Real-time Markdown preview — split-pane editor with instant rendering
• Mermaid diagrams — flowcharts, sequence diagrams, ER diagrams, Gantt charts, class diagrams, and more
• KaTeX math — inline and display mode LaTeX expressions
• Syntax highlighting — 16+ languages via Shiki with One Dark Pro theme
• GitHub-style alerts — NOTE, TIP, IMPORTANT, WARNING, CAUTION
• Tables and footnotes — full GFM support
• 100% client-side — your documents never leave your browser
• Zero tracking — no analytics, no cookies, no accounts
• Installable PWA — install CodeInk on desktop or mobile from supported browsers
• Local storage — documents saved via IndexedDB
• Offline-ready — /editor and /documents work offline after first load
• Markdown linting — real-time diagnostics via remark-lint with one-click auto-fix
• Multiple view modes — editor, split, and preview modes with resizable panes
• Export — Markdown export

Development

Prerequisites

• Bun installed on your system
• Node.js 18+ (optional)

Local Development

# Clone the repository
git clone https://github.com/jorgefl8/codeink.git
cd codeink

# Install dependencies
bun install

# Start development server
bun dev

The development server will start at http://localhost:4321

Build for Production

bun run build

PWA Notes

• First load must happen online so the service worker can cache app routes and assets.
• After that, /editor and /documents are available offline from cache + IndexedDB.
• Other static routes are best-effort offline and may show /offline if not cached yet.

Test PWA Locally

1. Run bun dev and open the app in Chrome.
2. Visit /editor and /documents once while online.
3. Open DevTools > Application > Service Workers and confirm registration.
4. Switch DevTools Network to Offline and reload /editor or /documents.
5. Verify install CTA appears when beforeinstallprompt is available.

License

This project is licensed under the MIT License. See the LICENSE file for details.