OpusPad transforms your Chrome browser into a robust local file editor with a Notion-like WYSIWYG experience. Seamlessly edit Markdown files (like CLAUDE.md, specs, or READMEs) stored on your local disk, without needing to open a full IDE or rely on cloud services.
🌐 Website: editor.dull.business
- Local-First: Your files stay on your disk. No cloud storage, no unnecessary uploads.
- WYSIWYG & Source Mode: Enjoy a beautiful Notion-like editing experience, or switch to the raw Markdown source mode when needed.
- AI-Ready: Perfect for managing and editing AI-generated content and specifications, like CLAUDE.md files, directly where you work.
- Chrome Integrated: Leverages the native File System Access API for direct local file manipulation.
- Lightweight: No need for heavy IDEs just to edit a few Markdown files.
Install OpusPad directly from the Chrome Web Store.
- Clone the repository:
git clone https://github.com/luanjunyi/opuspad.git - Navigate to the directory:
cd opuspad - Install dependencies:
npm install - Build the extension:
npm run build(This will generate adist/directory) - Load into Chrome:
- Open Chrome and navigate to
chrome://extensions/. - Enable "Developer mode".
- Click "Load unpacked" and select the
dist/directory.
- Open Chrome and navigate to
- Editing
CLAUDE.mdfiles for AI agent instructions. - Managing local specification documents.
- Quickly updating
README.mdfiles. - Any task requiring local Markdown file editing within Chrome.
OpusPad is truly local-first. It does not send your file content to any cloud server. All file processing happens locally in your browser.
- Not a full IDE: OpusPad is focused on Markdown editing and does not provide full development environment features.
- Binary Files: Designed for text-based files, primarily Markdown. It safely prevents opening unsupported binary files.
- React + Vite
- BlockNote
- CodeMirror
- Native File System Access API