Check if a PDF has been edited: detect tampering in a document
An invoice whose IBAN has changed, a quote with a retyped amount, a contract altered after it was signed? Certyneo Reader examines the PDF for the traces that editing usually leaves behind, then circles the affected areas on the page. These are clues, never proof. The analysis runs entirely in your browser: the file never leaves your device, with no account and no limits.
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How to check if a PDF has been modified in three steps
- 1
Open the PDF
Drag the document into the reader or pick it from your device, then open the Detect tampering tool.
- 2
Run the analysis
The save history, signatures, the file's internal information, fonts, page text and key values such as the IBAN, the company registration number or the totals are examined in a few seconds, on your device.
- 3
Read the verdict
The verdict says "no clues", "worth checking" or "strong clues", with a list of what was found and the affected areas circled on the page. If in doubt, contact the sender through a channel you already know.
Everything happens in your browser: the file never leaves your device. Open in the reader
Related tools and guides
- ↑ Free tools
- → Read a PDF online with nothing to install
- → Edit the text of a PDF
- → Annotate and highlight a PDF
- → Redact sensitive information in a PDF
- → Make a scanned PDF searchable with OCR
- → Compare two versions of a PDF
- → Reorder, rotate and delete pages
- → Merge several PDFs into one
- → Split a PDF into several files
- → Compress a PDF to send it by email
- → Password-protect a PDF
- → Convert JPG or PNG images to PDF
- → Sign a PDF online, step by step
Is this PDF authentic? Frequently asked questions
What kinds of tampering can the tool spot?
An amount or IBAN retyped in a different font from the rest of the document, text hidden under a white box, a value added on top of a scan, a file saved several times or modified after an electronic signature, a PDF editing program recorded in the file's information, inconsistent dates, an IBAN with wrong check digits, an invalid French SIRET number, and totals before tax, VAT and after tax that don't add up.
Does a clue mean the document is fake?
No. A clue is never proof: a genuine document may have been re-saved, corrected by its sender or converted with another program. A "worth checking" or "strong clues" verdict is an invitation to check the document with its sender, not to conclude there was fraud.
If no clue is found, is the document authentic?
Not necessarily. A fake invoice rebuilt from scratch, from a template or with invoicing software, leaves no trace of editing. No clues only means the checks that ran found nothing: for a payment or an important commitment, always confirm with the sender.
Bank details fraud: how do I spot a changed IBAN on an invoice?
The tool flags an IBAN retyped in another font, hidden and rewritten, or with wrong check digits. But valid check digits prove nothing: a fraudster can give a real account that belongs to them. Before paying a new IBAN, call the supplier on a number you already had, never the one on the document or in the email you received.
How can I stop my own documents from being forged?
Have them signed electronically and keep them in a digital vault. With Certyneo, a signed document is sealed: it can no longer be modified without the change showing, and anyone can check that it is intact. Analysing the PDFs you receive stays fully local: Certyneo never receives the document you are checking.
Does this PDF need to be signed?
Send it for electronic signature in minutes: your signers sign from their phone, without creating an account.
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