CopyCat

About

Your clipboard is being watched.
Every time you copy text, websites silently log that event — tracking what you highlighted, when you copied it, and whether you pasted it into an AI tool. CopyCat detects and blocks this in real time.
FEATURES
🛡 Shield Mode
Blocks websites from registering copy, paste, select, and drag event listeners entirely. They simply can't intercept what you copy.
🔖 Invisible Watermarking
Embeds a cryptographic HMAC-SHA256 signature into copied text using zero-width characters. If your writing shows up somewhere else, you'll know exactly where it came from.
🔒 Secure Copy (AES-256-GCM Encryption)
Encrypts clipboard contents so only CopyCat-enabled tabs can read what you copy. OS clipboard tools and other apps see encrypted garbage.
⏱ Auto-Clear Clipboard
Automatically wipes your clipboard after a configurable timeout so sensitive text doesn't linger.
📸 Screenshot Detection
Detects PrintScreen key presses and Snipping Tool activity on any page you visit.
🤖 AI Paste Detection
Detects when your copied content is pasted into ChatGPT, Claude, Gemini, Perplexity, and other AI tools — and flags watermarked content.
📊 Encrypted Activity Log
Keeps a local log of every surveillance attempt, copy event, and AI paste — stored with AES-256-GCM encryption. Nothing is ever sent to a server.
PRIVACY FIRST
Everything stays on your device. No accounts. No servers. No telemetry. The encryption key never leaves your browser.
NOTE: Chrome extensions do not run on Chrome for Android or iOS. CopyCat works on desktop Chrome, Edge, Brave, and other Chromium-based browsers.