Developer docs

Buyer verification

Verification is the free side of the system: a paying agent or platform checks a seller's attestation with no charge, no registration and no personal data. The check completes locally.

The verification path

  1. Fetch the verdict for the seller's endpoint identifier over the free

path. The verdict is a small signed document: operator status, guarantee-deposit state, verification date, and the renewal cadence promise.

  1. Check freshness against the cadence the credential itself promises —

the buyer never needs a clock authority beyond its own.

  1. Verify the signature locally. The verdict payload verifies with a

published public key (Ed25519) against the canonical byte form of the payload. No call to any ZadQ system is required at decision time.

verdict ──► freshness check ──► local signature check ──► badge state
   │              │                     │
   └── absent ────┴──── stale ──────────┴── invalid ──► "unknown"

Badge states

The badge shows one of three words. The verdict object carries the outcome (human_backed, revoked, stale, no_signal, with reason on any non-positive one); the copy-in badge snippet reduces it to three states.

BadgeVerdict outcomeSnippet stateMeaning
verifiedhuman_backedhuman-backedValid, fresh attestation; an accountable, verified operator with an active guarantee deposit stands behind the endpoint
not verifiedrevokedrevokedThe attestation has been withdrawn, or has lapsed past its renewal deadline
unknownstale, no_signal, or no verdict at allunknownNo usable verdict — stale, withheld, unreachable or unverifiable — the neutral fallback

Graceful degradation

unknown is a first-class state, not an error. Every integration keeps working when no verdict is available: the badge shows unknown and the payment flow proceeds exactly as it would without the attestation layer. Buyer-side policy — whether to pay unknown sellers — always belongs to the buyer, never to the verification layer.

What verification never requires

  • No account, key or credential on the buyer side.
  • No fee on the verification path.
  • No personal data in either direction.
  • No live dependency: a cached verdict inside its freshness window verifies

offline.

Next: the SDK reference lists the vendorable modules implementing this path.