Paste Guard checks what you paste into ChatGPT, Claude, Gemini and more. If it finds an email, API key, card number, Aadhaar, PAN or UPI ID, it offers to paste a masked version instead. Everything happens on your device.
Chrome Web Store: coming soon Try the interactive tour Try the scanner
Free. No account. No tracking. Nothing is uploaded: you can check that in your browser.
rahul.sharma@example.com, it pastes [EMAIL_1]. The same value always gets the same number inside one paste.Emails, phone numbers, cards, Aadhaar, PAN, UPI IDs, IFSC, GSTIN, IBAN, API keys from many providers, private keys and passwords in connection strings. See the full list.
Paste masked, paste anyway, or cancel. Press Ignore on a value and it is never flagged again.
No network requests, no analytics, no remote code, no account. On the sites listed below it checks what you paste and, with Restore on, reads the page text to show your original values again in replies. Nothing leaves your device.
The AI only sees placeholders like [EMAIL_1]. When it answers using them, your browser shows your real values again, on your device. Your message box keeps the placeholders, and Alt+R (Option+R on a Mac) switches the view. You can turn this off in the popup.
Select a client or project name in the message box and press Alt+Shift+M (Option+Shift+M on a Mac). It is masked now and in every future paste, using a personal dictionary kept on your device (up to 10 words, free).
The AI sees placeholders. You still read your own words.
Paste Guard keeps a short-lived list in memory so that when the AI answers using [EMAIL_1], your screen shows the real value again. Your message box always keeps the placeholder, and the AI never sees the original. Memory only, up to 4 hours, one button to forget it.
Select a client or project name in the message box and press one shortcut. It is masked now and in every future paste, from a personal list of up to 10 words that stays on your device.
With scripting on, hover, focus or press a chip to see a made-up example. It is a safety net, not a guarantee: it matches common patterns and can miss unusual formats.
Email addresses
name@example.com[EMAIL_1]
Made-up sample. Press a chip to see another.
The scanner page runs the same detector code as the extension, in your browser, on text you paste. It shows what would be found and the masked version. Nothing is uploaded.
After you install, a welcome page opens with a practice box that uses the real dialog. The scanner page is the quick way to try the detectors first.
You should not have to take our word for it. These checks take about five minutes.
Open chrome://extensions, click Details on Paste Guard. It asks only to read and change data on the AI sites listed below. Its only API permission is storage, for your settings.
On chrome://extensions turn on Developer mode, click Inspect views: service worker and open the Network tab. Then right-click the toolbar icon and choose Inspect popup, open its Network tab and change a setting. Both stay empty.
On a supported site, open DevTools, go to Network, and paste a fake key such as AKIA plus 16 capital letters. The warning appears and no request is made by the paste.
In the popup's DevTools console run chrome.storage.local.get(null, console.log). You will see settings, a counter and, if you used Ignore, one-way hashes. Never pasted text.
With Restore on, mask a fake value, then in the popup's DevTools console run chrome.storage.session.get(null, console.log): you will see a restore: entry for the site, held in memory. Run chrome.storage.local.get(null, console.log): the original value is not there. Keep the Network tab open while a reply is restored: no request is made.
The extension's JavaScript is delivered to your browser and can be inspected in the installed package. Open chrome://extensions, click Details on Paste Guard, then open DevTools on its popup or service worker (Inspect popup, or Inspect views with Developer mode on) and browse its files in the Sources tab. This site does not publish the source code.
Paste Guard does nothing on any other website.
Install, paste something sensitive, choose Paste masked, see values restored in replies, mask a word, and change settings. Silent, with captions and chapters.
Watch the tutorial Try the interactive tour
The video is a simulation on a stand-in chat page with made-up data. The warning window and the detectors are the real ones.