Frequently asked questions

It's a certificate (diploma, credential, ID card or record) issued in digital format that includes a unique serial and a QR code. Anyone can scan that QR or look up the serial to confirm the certificate is authentic, who issued it and to whom, without relying on a physical paper.

When you scan the QR or enter the serial on the public verification page, the official issuance details are shown: issuer, holder, date and status. The check is instant, free and requires no account.

Verification doesn't live on the paper, but on our platform, protected with enterprise-grade security. Copying the image of a certificate is useless: the serial and the QR always point to the original record, so any alteration is detected instantly.

Validity is granted by your organization as the issuer; ZERTI provides the technical proof of authenticity and integrity. Every certificate is recorded with its issuer, holder and date, and can be verified permanently as long as it's active.

When a certificate is issued, ZERTI computes its mathematical fingerprint (a unique number) and records it permanently on the blockchain via OpenTimestamps, at no cost. That proves the certificate existed on that date and hasn't been altered: if someone modifies it, the fingerprint stops matching and validation marks it as "Altered". No personal data is stored on the chain, only the fingerprint. You can learn more on the "Verifiable certificates" page.

It's a digital credential signed under the international Open Badges 3.0 standard (1EdTech / W3C), the same one used by universities and major platforms. In addition to the PDF, the participant receives a verifiable credential carrying your organization's cryptographic signature. Any verifier (employer, institution) can check who issued it and to whom, without depending on ZERTI. ZERTI's credential passes the official 1EdTech validator with no errors.

The seal doesn't block editing, but it exposes it: the fingerprint is recomputed on validation and, since it no longer matches the one sealed on blockchain, the validation page changes from "Intact" to "Altered". It doesn't prevent the change, it makes it impossible to hide. If the change is legitimate, the right thing is to revoke the certificate and issue a new one, which gets sealed with its own fingerprint and date.

No. Only a mathematical fingerprint goes to the blockchain (a number from which no data can be recovered). In the Open Badge credential, the email is hashed. The name, the PDF and the data live only in ZERTI. It's the same model MIT uses for its diplomas, and it's the right approach for data protection compliance.

From the validation page itself, with one click: a blockchain explorer for the proof of existence, and the official 1EdTech validator or CertLister for the Open Badge credential. None belong to ZERTI, so trust doesn't depend on us: anyone can check the proof independently.

Yes. You can customize your templates with your brand, colors and signatures, and on the plans that include it your certificates are verified on your own domain, with your identity front and center on every verification.

Yes, you get a free plan with 50 certificates in total to try the platform at no cost and no credit card. From there, the paid plans increase the volume, remove the ZERTI branding and add a custom domain, statistics and more. Check the pricing page.

Yes. You can upload your previous issuances so they're recorded and verifiable in ZERTI, so they also get their serial and their verification QR. If you have a large volume, write to us and we'll help you with the migration.