Anonymize a Word document before an AI reads it
Drop a .docx file. Names, companies, addresses, emails, phone, bank and ID numbers are replaced by codes in the body, headers, footers, notes, comments and tracked changes; the author and other metadata are removed; the layout stays as it was. Download the coded copy and give it to the AI.
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.
What a Word file hides, and what the coded copy does with it
Find-and-replace by hand misses most of what a .docx carries. The coded copy handles each part:
| In the Word file | In the coded copy |
|---|---|
| Body, headers, footers, footnotes, text boxes | Coded, formatting kept |
| Comments and tracked changes | Kept as coded text, such as [comment by NAME-002] |
| Author, last modified by, company, title, custom properties | Removed |
| Fields and hyperlinks, such as a mailto: link | Displayed text kept and coded, target removed |
| Images, embedded objects, template path, macros | Removed |
As a final check, the whole package is searched again for every value of the key. If one is still found anywhere, no copy is produced. Once the AI has written a Word document with the codes, drop it in the Restore tab to get the version with real names, formatting intact.
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
Will the layout of my document change?
No. Text is replaced inside the existing runs, so styles, numbering, tables and page layout stay as they were. Only images and embedded objects are removed.
What about a .doc file from an old version of Word?
Open it in Word and save it as .docx first. The free tool reads .docx only.
Can I restore a Word document written by the AI?
Yes, in the same browser tab: drop the .docx in the Restore tab and download the version with the real names.
Is a coded Word file anonymous under the GDPR?
No: it is pseudonymised, since the key can reverse it. What the AI receives no longer names anyone directly, and the key that could reverse it stays in your browser tab. Your obligations as controller of the original data remain.
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.