What a signed e-invoice certificate proves — and how to verify it

Every paid FacturProof check can return an evidence certificate: an Ed25519-signed record that we examined this exact document and reached this result at a given time. Anyone can verify it offline against our public key — no need to trust us, and no need to re-run the check.

What it binds

The signed payload pins the three things a dispute turns on:

• The document — its SHA-256 hash, so a certificate can never be moved onto a different file.
• The result — the VAT verdict, the consistency findings, or the conformance verdicts (PDF/A + EN 16931), exactly as we returned them.
• The time — when we checked, plus the issuer (facturproof.com) and the source (EU VIES, or the official veraPDF/KoSIT engines).

Three kinds of certificate

• VAT verification — proof a supplier's VAT id was valid on the invoice date, including the official EU VIES consultation number when issued (a third party can cross-check it with the tax authority).
• Invoice consistency — proof the document's own totals, tax and category reconcile (or exactly which do not).
• Conformance validation — proof the file passed (or failed) the official PDF/A-3 and EN 16931 checks, and which engines actually ran.

What it does NOT claim

Honesty is the whole point. A certificate is signed evidence of the check we ran and the source we used — not a legal guarantee that the invoice is perfect. A VAT certificate proves what VIES answered at time T; a conformance certificate proves what the official engines returned; an engine that did not run is reported as such, never as a pass. That is exactly what makes it trustworthy: it claims only what it can prove.

🇫🇷 Why it matters now: from 1 September 2026 a French business must be able to defend its input-VAT recovery and the invoices it processes. A signed certificate — verifiable by your auditor without trusting you or us — is stronger than a screenshot of a lookup.

Verify one yourself

Paste any certificate into the verifier — the signature is checked in your browser against the published key; nothing you paste leaves the page:

Open the certificate verifier →

# Or fetch the public key and verify with any Ed25519 library:
curl https://facturproof.com/v1/vat/attestation-key
# canonicalise the payload (sorted keys, compact separators) and check the signature.

Get an API key — free tier

FacturProof — e-invoice validation, consistency and VAT verification with signed, offline-verifiable attestations. Guidance on the standards, not tax or legal advice.

Check a VAT id → · Check invoice consistency → · PDF vs XML →