Anonymize an email before you ask an AI to answer it
Paste the email or the whole thread below. Names, signatures, addresses, phone numbers, email addresses and case references become codes. Ask ChatGPT or Claude to draft the reply on the coded version, then restore it here and copy it into your mail client.
Restoring uses the key of this tab: code your text here first, keep this tab open, then come back with the answer.
Adjust
See the key (it stays in this tab)
The key links each code to the real value. It exists only in this tab's memory: close or reload the tab and it is gone.
connect-src 'none' in its security policy) and loads no analytics. Turn Wi-Fi off once the page has loaded: the tool works just the same. The engine is the one inside the Hidden Tokens app.How it works
1 · Code
Paste a text or drop a file. Names, companies, addresses, emails, phone numbers, bank details, ID and case numbers become codes such as NAME-001 or COMPANY-001. Unknown proper nouns are coded too: when in doubt, the engine codes.
2 · Send the codes
Copy the coded text, or download the coded file, and give it to ChatGPT, Claude, Gemini or Copilot. The AI reasons on the codes: it still knows who did what, not who they are.
3 · Restore
Paste the AI's answer in the Restore tab, in the same browser tab. The codes become the real names again, on your screen only.
Emails are where client data leaks first
Answering email is the first thing people use AI for at work, and an email thread is dense with personal data: the sender's signature with a phone number, quoted replies, a date of birth mentioned in passing, a claim number in the subject line. Pasting the thread as it is sends all of it.
- Paste the whole thread, signatures included. The engine codes the names in greetings and signatures, the addresses, phone numbers, email addresses and references such as claim or case numbers.
- Read the warning, if there is one. A date of birth, a town and a job together can identify someone even without a name. The tool flags these combinations so you can remove what the AI does not need.
- Ask for the reply, then restore it. “Reply to
FIRSTNAME-001, polite but firm, deadline unchanged”. Paste the draft in the Restore tab and copy the version with the real names into your email.
The free tool or the Hidden Tokens app?
This free tool
- One text or one file at a time
- Up to 3,000 words or 1,000 spreadsheet rows
- The key lives in this tab and disappears when you close it
- Word, Excel, CSV and text
The Hidden Tokens app
- Whole folders: the same person keeps the same code in every document
- One key per case file, kept on your computer
- PDF and scanned documents, read on your computer
- Inside Claude Desktop, and in ChatGPT, Gemini and Copilot with the extension
- Industry packs, firm rules and a signed proof of what the AI saw
A word on the word “anonymize”
Strictly speaking, this tool pseudonymizes: each value is replaced by a code that can be reversed with the key. Under the GDPR, pseudonymised data is still personal data for whoever holds the key, which here is you, in this tab. What the AI receives no longer names anyone directly. Clues can remain, such as a job, a town and an age together: the tool warns you when it sees them. Read the result before sending it.
Questions
Does it code the signature block?
Yes: names, job titles next to a name, phone numbers, email addresses and postal addresses in a signature are coded like the rest of the text.
What about the email addresses in the To and Cc lines?
If you paste them, they are coded. You usually do not need them for the AI to draft a reply: leaving them out is even better.
Can I use this with Outlook Copilot or Gmail Gemini?
Copilot and Gemini inside your mailbox read the email directly, before you can code it. This tool is for the case where you paste the email into an AI yourself.
Is there a limit on length?
Up to 3,000 words per text, which covers a long thread. For whole mailboxes or folders, use the Hidden Tokens app.
Other ways to use the free tool
For whole folders, use the app
Hidden Tokens codes whole case files on your computer with one key, works inside Claude Desktop and in your browser, reads PDFs and scans, and puts the real names back into Word and Excel files.