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 get signed (quote, contract, mandate, non-disclosure agreement)? Certyneo lets you sign a PDF online without installing Acrobat, without printing or scanning, and without breaking the file's integrity. The electronic signature applied is eIDAS compliant, the signed PDF stays readable in any PDF reader, and each signature generates a timestamped audit trail 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 | Original PDF preserved, PAdES-sealed | SES, AES and QES | 5 envelopes for 14 days, then 2/month, no expiry | EU |
| Adobe Acrobat Sign | The following is a list of the | SES + AES + QES | Free PDF signing; 2 signature requests every 30 days | Not specified |
| Smallpdf | Not specified | Not specified | Signing without an account; 2 documents per month with a free account | Not specified |
| iLovePDF | Not specified | SES (AES on Premium) | Unlimited self-signing; limited signature requests | Not specified |
| DocuSign | Not specified | SES (AES on quote, QES as a paid option) | Free signer account; 3 send requests via the app | Not specified |
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 PDF is sealed in PAdES format, accompanied by a signature certificate and an audit trail. The cryptographic proof lets you verify that no page has been added or modified after signing.
- PAdES sealing of the original PDF
- Printed and preserved images
- Visible signature + cryptographic signature
- RFC 3161 timestamped 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
The signed, timestamped PDF, its signature certificate and the audit trail can be downloaded 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.
To proofread a PDF before sending it, or to view a document you received without installing any software, use our free online PDF reader
Does the contract need reviewing first? Highlight the clauses to discuss and add your remarks before sending it for signature: annotate a PDF online, with no account or installation
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 complies with the eIDAS Regulation (EU) 910/2014. Certyneo generates simple, advanced and qualified signatures compliant with this regulation: all of them are admissible in court in the European Union, and only the qualified signature has the same value as a handwritten signature in every Member State.
- 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 works entirely in the browser, with no installation. The free plan covers 5 envelopes for 14 days, then 2 per month, with no expiration and no credit card required.
- Can we get a PDF signed by more than one person?
- Yes. You can add several signers, within the limit of your plan (2 per envelope on the Free plan, 5 on Personal, 15 on Standard), define a sequential order (signer A then signer B) or let everyone sign in parallel. Each signature generates its own proof of identity in the shared 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 several signers, in parallel or in a set order, within the limit of your plan (2 per envelope on the Free plan). 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.