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Check an AEAT CSV instantly

Paste a Secure Verification Code and we'll tell you if the format matches an official AEAT CSV, what type of document it likely is, and take you straight to the official verification page so you can see the original document. 100% in your browser.

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No login · No certificate · No data sent to any server

CSV to verify

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Official verification happens at sede.agenciatributaria.gob.es. This tool only prepares the link.

What is it?

The CSV is public proof that a document exists at the AEAT

Identifies the document

Every electronic document the AEAT receives (VeriFactu invoice, filed tax form, official request, notice) gets a unique CSV. That code is the document's "license plate" in AEAT systems.

Public and searchable

Anyone with the CSV can look up the original document at the AEAT online office — no certificate, no login. That's why it appears in the QR code on VeriFactu invoices: the AEAT designed it to be public.

Stays valid indefinitely

A CSV identifies the document for as long as the AEAT keeps the record (a minimum of 4 years under the statute of limitations, in practice indefinite). Useful when someone asks for proof of something you filed years ago.

Formats

The 3 CSV formats you'll see

The tool detects which one automatically. They cover 95% of cases; the AEAT may use others in specific sub-systems.

1 VeriFactu / SII

Pattern 1 letter + hyphen + 14 A-MMURGK5EJUWRZU

VeriFactu invoices and SII records submitted via web service.

2 Classic verification

Pattern 16 alphanumeric 7AB2CDEF9876543E

The historical format for verifying electronic documents.

3 Extended verification

Pattern 20 alphanumeric

Common in official notices and long resolutions.

Inside Cofactu

Every invoice keeps its CSV — with verification one click away

You don't have to paste codes by hand. When the AEAT accepts an invoice, Cofactu stores its CSV in the audit log with cryptographic custody and leaves the verification button ready. If someone asks you for proof, it's in the invoice detail.

The verification link opens the AEAT online office with the CSV pre-loaded — no certificate, no login.

What it's for

When do you need to check a CSV?

Audit your own VeriFactu submissions

Cofactu stores every CSV with an immutable audit log, but sometimes you want to manually confirm with the AEAT that a specific submission was recorded. Paste the CSV → verify → see the original XML the AEAT received.

Verify invoices you receive

If a supplier sends you an invoice claiming to be VeriFactu, its QR code contains a CSV. Verifying it confirms the invoice actually exists at the AEAT (it isn't made up). Useful for internal audits and for exercising the recipient's right to check.

Defend yourself against an official request

If the AEAT asks you about something you already filed, the CSV from your original submission is the fastest proof — point to the AEAT online office with the CSV and the AEAT itself confirms its own record. Cofactu stores the CSV in the detail view of every filed tax form.

Validate official requests / notices

If you receive a physical or email notification claiming to be from the AEAT, the CSV printed on it lets you confirm at the online office that the AEAT actually issued it. If nothing comes up when you check, suspect phishing.

FAQ

Frequently asked questions

What exactly is an AEAT CSV?

CSV stands for Código Seguro de Verificación (Secure Verification Code). It's an alphanumeric identifier (typically 16 characters) that the AEAT automatically generates every time it receives and processes an electronic document — VeriFactu invoices, tax forms, resolutions, requests, official notices. It serves as proof that the document exists in AEAT systems, and lets anyone (not just the signer) check it at the AEAT online office.

How do I actually verify a CSV?

You need to go to the AEAT online office — document verification (Cotejo), paste the CSV, and click check. The office shows you the original document linked to that code. You do NOT need a digital certificate to do this check (it's public) — just the full CSV. This tool validates the format and generates the direct link, but the real verification happens on the AEAT site.

Why doesn't this validator check whether the CSV actually exists in AEAT?

Because the AEAT doesn't expose a public, unauthenticated API to look up CSVs. Only the web verification form. Automating that check would mean scraping the HTML, which is fragile (any AEAT change breaks it) and outside the online office's Terms of Use. The real verification is one click away, and you do it yourself.

What AEAT CSV formats exist?

Three documented ones: (1) Modern VeriFactu / SII type — 1 letter + hyphen + 14 alphanumeric characters (e.g. A-MMURGK5EJUWRZU). (2) Classic verification — 16 alphanumeric characters with no hyphen (e.g. 7AB2CDEF9876543E). (3) Extended verification — 20 alphanumeric characters, common in official notices and long resolutions. The AEAT may use other formats in specific sub-systems, but these three cover 95% of cases.

What does the 'A-' prefix on my Cofactu invoice CSVs mean?

The 'A' prefix identifies a billing record submitted via the AEAT web service with a server electronic seal — which is exactly Cofactu's VeriFactu flow. In Cofactu, every invoice accepted by the AEAT gets a CSV of this type, stored in your audit log with cryptographic custody plus a direct link to the online office for verification.

How long is a CSV valid for?

Indefinitely. A CSV identifies a specific document in AEAT systems and stays queryable for as long as the AEAT keeps the record (a minimum of 4 years under tax statute of limitations, in practice indefinite for relevant records). If you look up an 8-year-old CSV, the online office still shows you the original document.

Is it safe to paste my CSV into third-party tools?

The CSV itself isn't sensitive information — the AEAT online office lets anyone check it without authentication, so anyone with the code can see the document it points to. That's exactly why the CSV is printed in the QR code on VeriFactu invoices: it's designed to be public. Either way, this tool does 100% of the validation in your browser and sends nothing to any server — you could disconnect from the internet and it would still validate the format.

Cofactu stores every CSV in your audit log

Every VeriFactu invoice and every AEAT tax form filed from Cofactu keeps its CSV with cryptographic custody plus a direct link to verify it at the online office. If the AEAT asks, it's one click away.

Try Cofactu for free See tax form filing