Guide
Redact a PDF.
To redact is to remove a piece of data from a document, not to cover it. Anoni finds the personal data in the PDF, you check it, and it writes a new PDF where that data no longer exists. Nothing is uploaded.
Need to get the real data back later? That is not redaction, it is pseudonymization: pseudonymization or redaction.
Updated 29 October 2026
- 01
Drop the PDF onto Anoni
The home screen asks « What would you like to anonymize? ». Drag the PDF in (« Drop to open ») or pick it from the disk. The analysis starts on its own.
- 02
Check what will be redacted
The « Check » step highlights each piece of data found: names, addresses, phone numbers, emails, IBANs, company numbers, dates. Click a highlighted word to keep it; click a plain word to redact it. The « Redacted preview » shows the page as it will come out.
- 03
Cover what is not text
A signature, a stamp, a photo: the « Black zone » tool draws a box by hand. It works on PDFs and images.
- 04
Choose « Redact » and save
At the « Export » step, « How to share? » offers two choices. « Redact » is the irreversible one: black bars, text removed. Click « Save the redacted PDF » and choose where to put it.
- 05
Let Anoni re-read the file
Once written, Anoni re-reads the PDF it produced (« Checking the file… ») before it shows « Saved and checked ». The original PDF is not touched.
Why a black box is not enough.
In a PDF editor or a word processor, a black box drawn over a name removes nothing. The text is still underneath: you can select it, copy it, find it with a search. The author's name and the title also stay in the document properties. It is the most common redaction mistake.
What Anoni writes instead.
Each page is redrawn as an image, the bars are painted onto the image, then Anoni writes a new PDF made of those images. The original text is not copied over: there is nothing left to select. The original file properties, such as author or title, do not carry over either. On a test PDF whose properties held a name, the redacted file had neither that name nor a single copyable character.
What it costs.
The redacted PDF has no text layer anymore: you cannot search it for a word or copy a paragraph. That is the price of safe redaction. Keep the original for yourself, send the redacted version.
A scanned PDF.
A scan has no text, only images. Anoni reads it with on-device text recognition, then redacts as it would an ordinary PDF. A page that no reading can make out is covered whole rather than left readable. Check the preview: text recognition can miss a handwritten name.
Free, with a watermark.
PDF redaction is part of the free version. The exported PDF then carries an « anoni.dev » watermark, which Anoni announces before saving. Anoni Pro removes it.
Nothing leaves your computer.
The PDF is read, analysed and redacted on your machine. It is not sent anywhere, and everything works offline once Anoni is installed.
Frequently asked
Can the black bars be removed?
No. The text is no longer in the file: there is nothing under the bars. If you need the real data back later, pseudonymize instead of redacting.
What about a Word document?
The same flow also saves a redacted Word document: the data is replaced with bars, and the document stays editable.
Is redaction free?
Yes, with an « anoni.dev » watermark on the pages of the exported PDF. Anoni Pro removes it.
Which systems?
macOS, Windows and Linux.
To redact your first PDF, download Anoni. See also pseudonymization or redaction, data anonymization and the other guides.
More guides
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- 27 September 2026Watermark a PDFOne sentence repeated on every page, baked into the image. Free, local, and it does not peel off.
- 29 October 2026Protect your rental applicationYour documents go out to strangers, several times over. A watermark says what they are for, and what they are not for.