Anonymize log files and JSON before you ask an AI to debug them
Paste the log lines, the stack trace or the JSON payload below. Emails, card and phone numbers, IP addresses, user IDs and customer names become codes; keys, field names and status values stay readable so the AI can still follow the error. Paste the coded version into ChatGPT, Claude or Copilot.
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.
Example: a failed payment, one log line and its JSON
2026-11-03T10:42:17Z error payment failed user_id=48213 email=lucy.fairbairn@example.com card=4111 1111 1111 1111
{"customer": {"name": "Lucy Fairbairn", "phone": "+44 7700 900314", "city": "Bristol"}, "amount": 49.90, "status": "declined", "reason": "insufficient_funds"}2026-11-03T10:42:17Z error payment failed user_id=ID-001 email=EMAIL-001 card=CARD-001
{"customer": {"name": "FIRSTNAME-001 NAME-001", "phone": "PHONE-001", "city": "Bristol"}, "amount": 49.90, "status": "declined", "reason": "insufficient_funds"}The email, test card number, user ID, name and phone are coded; the log level, the JSON keys, the amount and the decline reason stay readable, so the AI can still explain the failure.
What developers paste, and what it contains
When a payment fails in production, the fastest move is to paste the log into an AI. That log usually contains the customer: their email, their name, sometimes a card number or an access token. Coding first keeps the debugging and drops the customer.
- Coded: emails, phone and card numbers, IBANs, IP addresses, identifiers next to keys such as
user_id=, and names inside string values. - Readable: JSON keys, timestamps, status codes, amounts, and ordinary words such as
declined. Capitalised technical words may be coded out of caution: keep them readable under Adjust. - Not handled: secrets such as API keys and tokens are not reliably recognised by the free tool. Remove them by hand before pasting anything, coded or not.
The free tool takes .txt files and pasted text; save a .log or .json file as .txt, or paste it. The coded output is text: it may no longer be valid JSON if a code replaced a number, so do not feed it back into a parser. The Hidden Tokens app reads .log, .json and configuration files on your computer and keeps one key across a whole project.
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 AI still find the bug?
Usually yes. Stack traces, field names, error messages and values such as amounts stay readable. What it loses is who the customer is, which it does not need.
Does it remove API keys and passwords?
Do not rely on it for that. Secrets have no fixed shape, and the free tool is built for personal data. Delete keys and tokens yourself before pasting a log anywhere.
Can I drop a .log or .json file?
Not directly: the file tab takes .txt, .md, Word, Excel and CSV. Rename a copy to .txt or paste the content. The limit is 3,000 words.
Is the coded JSON still valid?
Codes replace values inside strings, so the structure usually survives, but a coded number becomes text. Treat the output as something to read, not to parse.
Other ways to use the free tool
By file type
By AI tool
By task
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.