Electronic signature PDF: sign a PDF online in 30 seconds and you can do it in less than 30 seconds
Do you have a PDF to sign (statutes, contract, warrant, confidentiality agreement)? Certyneo allows you to sign a PDF online without installing Acrobat, without printing-scanning, and without breaking the integrity of the file. The electronic signature is eIDAS compliant, the PDF remains readable on any PDF/A compatible reader, and each signature generates a timestamped audit trail that is admissible in court.
Comparison of signature solutions in 2026
| The solution | The following is a summary of the information: | The eIDAS compliance | Free plan | Accommodation |
|---|---|---|---|---|
| Certyneo | PDF/A preserved + visual stamp | SES + AES | 5 PDF/month, permanent | EU |
| Adobe Acrobat Sign | The following is a list of the | The SES + AES + QES | 7 days trial | US (Adobe Cloud) is a software company. |
| Smallpdf | PDF reformatted | SES only | 2 PDF/day only | The Swiss |
| iLovePDF | Image pasted in the PDF | Not eIDAS | Limited, with watermark | Spain |
| DocuSign | PDF reformatted | SES + AES | 30 days trial | Global / EU option |
Why sign your PDFs with Certyneo
Certyneo is designed to preserve the integrity of your PDFs: no reformatting, no destructive compression, no watermark. The original file is encapsulated in a digitally signed PDF/A, accompanied by a signature certificate and audit trail.
- PDF/A long term (archiving for 10 years)
- Printed and preserved images
- Visible signature + cryptographic signature
- Qualified time-stamped audit
- Acrobat Reader, MacOS Preview and Foxit are also supported
- Multi-signature in parallel or sequence
- Integrity check with one click
How to sign a PDF online in 3 minutes
- 1
Import your PDF
Drag and drop the file into Certyneo, size up to 50 MB, up to 200 pages.
- 2
Place the signature fields
Click on the place where each signatory must sign, add a date, a preface or a check box if necessary.
- 3
Indicate the signatories
You can set a signature order or let everyone sign in parallel.
- 4
Send the request for signature
Each signer receives a secure email link valid for 30 days.
- 5
Download the signed PDF
PDF/A time stamped + certificate of signature + audit trail downloadable as soon as everyone has signed.
What PDF formats does Certyneo accept?
All standard PDFs (PDF 1.4 to PDF 2.0), including interactive PDF forms with AcroForm fields. PDF/A-1, PDF/A-2 and PDF/A-3 are preserved as is. If your PDF is an image scan, Certyneo accepts this too but we recommend OCR beforehand to preserve the text selection. Password protected PDFs must be unlocked before import.
Three ways to sign a PDF: which one to choose?
Not all “PDF signatures” are equal in the eyes of the law. Three approaches coexist:
The pasted signature image
Scanning or drawing your signature and inserting it into the PDF only creates an image, with no cryptographic link to the document: easy to copy, impossible to verify, and of almost no evidential value in a dispute.
The local certificate (PDF reader, smart card)
Signing with a certificate installed on your machine produces a real digital signature, but means buying and renewing a certificate — and the recipient must do the same to countersign.
The online signing platform
The document is signed in the browser: signer authentication (email, OTP code), PAdES sealing, timestamping and audit trail, with no certificate to buy and no software to install. It is the simplest eIDAS-compliant way to sign a PDF with several parties.
Signed PDF: how to verify the signature?
Open the PDF in a compatible reader (the “Signatures” panel shows the document's integrity and the certificate's validity). You can also use our free tool: verify a signed document →
Frequently asked questions on electronic signature
- Does an electronic signature affixed to a PDF have the same legal value as a handwritten signature?
- Yes, provided the solution is eIDAS compliant.Certyneo generates SES (simple) and AES (advanced) signatures compliant with Regulation (EU) 910/2014, which have the same probative value as a handwritten signature in a European court.
- Is my signed PDF still readable by Acrobat Reader?
- Yes. The signed PDF remains a standard PDF that can be read in Acrobat Reader, Preview (macOS), Foxit, or any compatible PDF/A reader. Acrobat Reader also displays a validation bar indicating that the signature is cryptographically valid.
- How do you check that a signed PDF has not been modified after signing?
- The signed PDF contains a cryptographic seal calculated on the entire file at the time of signing. Any subsequent modification (even a changed comma) breaks the seal and causes a warning to appear in Acrobat Reader. Certyneo also provides an online verification tool.
- Can you sign a PDF for free without installing software?
- Yes. Certyneo runs entirely in the browser, no installation. The free plan covers 5 PDFs per month, no expiration and no credit card.
- Can we get a PDF signed by more than one person?
- You can add as many signers as you need, set a sequential order (signer A then signature B) or let everyone sign in parallel. Each signature generates its own proof of identity in the common audit trail.
- How can I sign a PDF for free?
- Create a free account: the Free plan lets you sign and send PDFs for signature without a credit card. The simple signature suits everyday documents; paid plans add the advanced signature with SMS OTP and higher volumes.
- How do I sign a PDF on mobile?
- Open the signing link received by email on your smartphone: the document opens in the browser and you sign with your finger or in one tap, with no app to install. iOS and Android are supported.
- Can several people sign the same PDF?
- Yes: add as many signers as needed, in parallel or in a set order. Each one receives an invitation, signs in turn, and the final PDF consolidates all the signatures with a single audit trail.
- Is signing a PDF online legal?
- Yes: the eIDAS regulation recognises the electronic signature of a PDF as long as the process identifies the signer and guarantees the document's integrity. PAdES sealing and the audit trail provide exactly those guarantees.