Labels · verification

A label is a receipt, not a certificate

A certificate says somebody approved you. A label should say what was measured, by whom, against which rules — and let anyone recheck it.

ZERO CARBON VERIFY · ESTABLISHMENT NOTE · 5 MIN READ

Most carbon labels are decoration with a logo. They assert a conclusion and withhold the working, which makes them impossible to audit and trivial to fake.

What a label actually contains

The label records we write carry fourteen fields and a hash. The fields are the claim; the hash is the mechanism that stops the claim being edited after the fact.

Field group	What it holds	Why it is there
Identity	label id, batch, issue date, expiry	Can be tied to physical goods
Method	version, hash, boundary, GWP set	Two labels are comparable only on the same method
Result	per-unit, total, baseline, reduction	The number and the denominator
Quality	metered share, grade, interval	How much is measured rather than assumed
Provenance	verifier, status, liabilities	Who signed and what they are allowed to claim

The hash is the point

Each label commits to its payload and to the previous label's hash:

hash = fnv( prev_hash + batch | total | per_unit | grade )

That structure makes the register append-only. You cannot quietly revise a number without breaking every label after it, and anyone with the published fields can recompute the chain themselves. Our own server is a convenience, not an authority.

What this is not

Not a carbon credit. Nothing on our labels is tradable, and we will not describe it as an offset.
Not an accreditation. Until the body is accredited, every document says so.
Not a quality mark. A low-carbon plantlet can still be a bad plantlet. Different question, different liability.

Try it on the register

The verification page recomputes the chain in the browser, with no server call. If you change a digit in the payload, the check turns red — which is the only demonstration of integrity that is worth anything.

Talk to us ← All insights

This note describes our method and commercial position. It is not a verification statement and carries no assurance. Under the two-track plan the certification conclusion is signed by a licensed partner; this site issues the method, the evidence grades and the register.