How do I issue certificates and letters that anyone can verify by QR code?
Sign the certificate PDF in Sealique: every signature block prints a QR code and verification ID, and page marks let anyone check a printout for tampering online.
Schools, training providers, associations and public offices issue documents that other people must trust: certificates of completion, diplomas, recommendation letters, clearance letters, licences. A forged copy is easy to make with any editor; a sealed PDF is not, because the verification page compares the file with the copy kept at sealing time and shows the result to anyone who scans the code.
Issue a verifiable PDF Create an account Verify a signed document
Key facts
- Every signature block on a Sealique-sealed PDF prints a verification ID (VF-XXXXXX-XXXXXX) and a QR code that opens the public verification page.
- A page mark is a small QR with the signer's symbol that can be placed on every page; each mark links to that exact page, so a single printed page can be checked.
- Verification is public and needs no account: scan the QR code, type the ID or upload the PDF; the result shows the signers, the sealing time and whether the file changed.
- The sealed PDF and its certificate of completion are kept in private storage; only the holders can download them, while the verification result stays public.
- Certificates can be signed by one issuer or by several people in sequence, for example the trainer and the director.
How does a QR code prove a certificate is genuine?
When Sealique seals a PDF it stores the file's SHA-256 fingerprint, a fingerprint of every page and a hash of every page's text, then signs the file with a platform certification signature and one PAdES signature per signer. The QR code in the signature block links to the verification page for that verification ID. The page shows who signed, when, and compares an uploaded copy with the sealed one, so an edited certificate is reported as modified after sealing and an unknown document as not found.
What is a page mark and why do I need one?
A certificate is often printed, and a printout has no digital signature. A page mark is a small QR code with the signer's symbol placed on a page; it encodes the page number and a digest of that page's content, so scanning it opens a result for that specific page. A forged page carries no valid mark, and a mark copied from another document points to a different page digest.
How do I issue many certificates at once?
Prepare each certificate as a PDF (for example from a template merged with the recipient's name), then sign them one by one in Quick Sign or create them through the API, one request per certificate: each call creates a document and sends it to the issuer (or the signers you name) to sign; the API never signs on your behalf. Once the document is sealed, the API returns its verification URL. Each certificate receives its own verification ID; the recipient can share the PDF or a photo of the QR code.
How does a recipient or employer verify a certificate?
They scan the QR code with the phone camera, type the verification ID on the verification page, or upload the PDF they received. No account is needed and nothing is installed. The result names the issuer, the signing time and the integrity status; e-mail addresses are masked on the public page.
Verifiable certificates, step by step
Prepare the certificate PDF
Create it from your template, or convert a picture or scan to PDF with the image to PDF tool.
Sign it in Quick Sign
Place your signature; add your symbol on each page so a printout can be checked too.
Seal and download
Press Sign & seal: the PDF now carries the QR code, the verification ID and the page marks.
Hand it out
Send the PDF or print it; the recipient and anyone they show it to can verify it online.
Verifiable certificates is included with a Sealique account; the processing happens in your browser and on our servers, nothing is shared with third parties.
What Verifiable certificates includes
- QR code and verification ID in every signature block
- Page marks that let a single printed page be checked
- Public verification page, no account, nothing to install
- Sealed copy and certificate of completion kept for the holders
- API to create one document per certificate, collect the signature and verify the result
Questions people ask
Can a verification QR code be faked?
A QR code can be copied, but it opens the verification page of one specific document, whose signers and fingerprint will not match the forged copy.
Do recipients need an account to verify a certificate?
No. Verification is a public page: scan the code, type the ID or upload the PDF.
Can I verify a printed certificate?
Yes, when it carries a page mark: scanning the mark checks that exact page; the QR code in the signature block confirms the whole document.
Does the verification page reveal personal data?
It shows the signers' names, titles and organisations and the signing time; e-mail addresses are masked and the sealed PDF opens only for the holders.
Can several people sign a certificate?
Yes. Invite the signers in order or at once; the sealed PDF carries every signature and one verification ID.