Maskeraid - LLM Data Mask Extension

A browser extension that automatically sanitizes Personally Identifiable Information (PII) and sensitive data from your prompts before sending them to Large Language Models (LLMs) like ChatGPT, Claude, and Gemini.

Download here:

• Microsoft Edge Store
• Firefox Add-ons store
• Chrome Web Store

What It Does

Maskeraid protects your privacy by automatically applying custom sanitization rules to mask or replace sensitive information in your prompts. This includes:

• Email addresses - Replace with masked versions
• Phone numbers - Mask digits while preserving format
• Credit card numbers - Replace with safe placeholders
• SSN/Social Security Numbers - Mask sensitive digits
• Custom patterns - Create your own regex or string replacement rules
• Real-time preview - See what will be sent before submitting

The extension works seamlessly on:

• ChatGPT (chat.openai.com, chatgpt.com)
• Claude (claude.ai)
• Gemini (gemini.google.com)
• Huggingface Chat (huggingface.co/chat)

Upcoming support for more LLM platforms!

• Perplexity AI (perplexity.ai)
• Microsoft Copilot (copilot.microsoft.com)
• T3 Chat (t3.chat)
• Z AI Chat (chat.z.ai)

and more...

Contributions are welcome! Please feel free to raise issues or contribute to the project.

How to Use

1. Install the Extension

1. Clone this repository
2. Build the extension: npm run build
3. Open Chrome and navigate to chrome://extensions/
4. Enable "Developer mode" (top right)
5. Click "Load unpacked" and select the dist folder

2. Configure Sanitization Rules

Click the extension icon to open the popup:

• Rules Tab: Create, edit, and manage sanitization rules

  • Click "Add Rule" to create a new rule
  • Define pattern (regex or plain text)
  • Set replacement text
  • Enable/disable rules as needed

• Settings Tab: Configure extension behavior

  • Enable/disable auto-sanitization
  • Toggle overlay visibility
  • Select which sites to enable
  • Choose theme (light/dark/system)

3. Use on LLM Sites

When you visit ChatGPT, Claude, or Gemini:

1. Type your prompt in the text area
2. The extension automatically detects and sanitizes sensitive data
3. A preview overlay shows what will be sent (if enabled)
4. Submit your prompt with confidence

Tech Stack

• React 19 - Modern UI framework
• TypeScript - Type-safe development
• Vite - Fast build tool and dev server
• Tailwind CSS v4 - Utility-first styling
• Radix UI - Accessible component primitives
• Chrome Extension APIs - Manifest V3
• Shadow DOM - Style isolation for content scripts

Key Dependencies

• @radix-ui/* - Accessible UI components
• class-variance-authority - Component variants
• clsx & tailwind-merge - Class name utilities
• diff - Text diffing for preview
• lucide-react - Icon library

Local Development

Prerequisites

• Node.js 18+ and npm
• Chrome browser

Setup

# Install dependencies
npm install

# Start development server with HMR
npm run dev

# Build for production (chromium browser)
npm run build

# Build for production (firefox browser)
npm run build:firefox

# Type check
npx tsc --noEmit

# Lint code
npm run lint

# Preview production build
npm run preview

Development Workflow

1. Make changes to source files in src/
2. Build the extension: npm run build
3. Reload the extension in chrome://extensions/
4. Test on supported LLM sites

Project Structure

src/
├── background/     # Service worker for cross-context communication
├── content/        # Content scripts injected into LLM sites
│   └── sites/      # Site-specific handlers (ChatGPT, Claude, Gemini)
├── popup/          # React popup UI components
├── components/ui/  # Reusable UI components (shadcn/ui pattern)
├── shared/         # Shared utilities, types, storage, sanitizer
└── lib/            # Utility functions

Build Output

The dist/ folder contains:

• manifest.json - Extension manifest
• background.js - Service worker
• content.js - Content script bundle
• index.html & assets - Popup UI
• icons/ - Extension icons

Features

• ✅ Custom Rules - Create regex or plain text replacement rules
• ✅ Real-time Preview - See sanitized text before sending
• ✅ Multi-site Support - Works on ChatGPT, Claude, and Gemini
• ✅ Smart Overlay - Optional preview overlay with diff highlighting
• ✅ Rule Management - Enable/disable, edit, delete rules
• ✅ Dark Mode - System-aware theme support
• ✅ Persistent Storage - Rules and settings saved locally
• ✅ Type-safe - Full TypeScript support

Credits

• Name suggestion: The creative name "Maskeraid" was suggested by @datarat23

License

This project is licensed under the MIT License - see the LICENSE.md file for details.

Author

• Ayush Walekar - GitHub
• Email - walekarayush@gmail.com
• Website - ayushwalekar.com