How to verify a certificate
A certificate is a claim about a retirement on a public registry. Here is how to check that claim yourself — and what to do if something does not add up.
What a genuine certificate carries
Every certificate has one, and every number resolves on our verification page. A number that does not resolve was not issued by us.
The QR opens the verification page with the certificate’s key, which is what lets the page show the holder’s name. Without the key the retirement is still public; the person is not.
The first sixteen characters of a hash of the certificate’s facts. The full hash is on the verification page; the two must agree. Certificates issued since signing began also carry a signature that anyone can check against our published key.
The registry the credits were retired on is named, and when the supplier returned a record link the page states it. A confirmation that rests only on a supplier’s statement says so.
What you can check yourself
- 01 Look the number up
Enter the certificate number on the verification page, or scan its QR code. The page shows the tonnes, the project, the registry and the dates — from the same record the PDF was printed from.
- 02 Follow the registry record
When a retirement record link is on file, open it. It sits on the registry’s own site, not ours, and names the same serials and beneficiary.
- 03 Check the file
On the verification page, choose the PDF you were sent. Your browser hashes it and we say whether it is the copy we issued. Nothing is uploaded.
- 04 Check the ledger
Every certificate we issue, withdraw or correct is an entry in a public, append-only log whose daily root is published on our transparency page and in our newsletter. A certificate’s entry and its proof are on its verification page.
What a fake usually looks like
- A certificate whose number does not resolve on our verification page, or resolves to different facts.
- A PDF that arrives from a domain other than ours, or a verification link that does not point at our site.
- A retirement with no registry record and no serials — a supplier’s word alone, on a large or expensive claim.
- A “registry” we do not list, or a record page that does not name the serials on the certificate.
- Pressure to buy credits as an investment, or to pay a reseller you cannot find on any registry. We sell retirements, not tradeable credits.
Report a suspected fake
If you hold a certificate that fails these checks, or were offered one, tell us. We will confirm whether it is ours, and if it is not, say so in writing you can pass on.
Report a certificate