PDF electronic signature: sign a PDF online in 30 seconds
Do you have a PDF to get signed (quote, contract, mandate, confidentiality agreement)? Certyneo allows you to sign a PDF online without installing Acrobat, without printing-scanning, and without compromising file integrity. The electronic signature applied is eIDAS compliant, the PDF remains readable on any PDF/A compatible reader, and each signature generates a timestamped audit trail admissible in court.
Comparison of PDF signature solutions in 2026
| Solution | PDF Format | eIDAS Compliance | Free plan | Hosting |
|---|---|---|---|---|
| Certyneo | PDF/A preserved + visual seal | SES + AES | 5 PDFs/month, permanent | EU (Germany) |
| Adobe Acrobat Sign | Native Adobe PDF | SES + AES + QES | 7-day trial | US (Adobe Cloud) |
| Smallpdf | Reformatted PDF | SES only | 2 PDFs/day only | Switzerland |
| iLovePDF | Image pasted in PDF | Non eIDAS | Limited, with watermark | Spain |
| DocuSign | Reformatted PDF | SES + AES | 30-day 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 an audit trail. Cryptographic proof allows you to verify that no pages have been added or modified after signing.
- PDF/A long-term (10-year archiving)
- Fonts and images preserved
- Visible signature + cryptographic signature
- Qualified timestamped audit trail
- Compatible with Acrobat Reader, macOS Preview, Foxit
- Multi-signers in parallel or in sequence
- Integrity verification in 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 where each signer should sign. Add date, initials or checkbox if needed.
- 3
Indicate the signers
Email is enough. You can set a signing order or let everyone sign in parallel.
- 4
Send the signature request
Each signer receives a secure email link, valid for 30 days. No account required to sign.
- 5
Retrieve the signed PDF
Timestamped PDF/A + signature certificate + 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 a scanned image, Certyneo accepts it too but we recommend OCR beforehand to preserve text selection. Password-protected PDFs must be unlocked before import.
Frequently asked questions about PDF electronic signature
- Does an electronic signature on a PDF have the same legal value as a handwritten signature?
- Yes, provided the solution complies with eIDAS. Certyneo generates SES (simple) and AES (advanced) signatures compliant with Regulation (EU) 910/2014, which have the same probative value as a handwritten signature before a European court.
- Will my signed PDF remain readable by Acrobat Reader?
- Yes. The signed PDF remains a standard PDF that can be opened in Acrobat Reader, Preview (macOS), Foxit, or any PDF/A-compatible reader. Acrobat Reader additionally displays a validation bar indicating that the signature is cryptographically valid.
- How to verify that a signed PDF has not been modified after signature?
- The signed PDF contains a cryptographic seal calculated over the entire file at the time of signature. Any subsequent modification (even a single comma changed) breaks the seal and triggers a warning in Acrobat Reader. Certyneo also provides an online verification tool.
- Can you sign a PDF for free without installing software?
- Yes. Certyneo works entirely in the browser, with no installation. The free plan covers 5 PDFs per month, with no expiration and no credit card required.
- Can a PDF be signed by multiple people?
- Yes. You can add as many signatories as needed, define a sequential order (signatory A then signatory B) or let everyone sign in parallel. Each signature generates its own proof of identity in the common audit trail.