Never let anyone forge
a certificate of yours again.
Fake diplomas and certificates are now AI-made in seconds. Issue credentials that any company can verify in one click —without calling you and without trusting anyone—: every certificate carries a seal anchored in Bitcoin that proves it is authentic and untouched, and stays verifiable even if you or we disappeared. Your brand protected, your alumni backed for life.
Partnership agreement — June
This certificate doesn’t exist.
And you can’t tell.
An AI generated it in seconds —the institute, the person, the gold seal, even the signatures. To the eye it’s perfect. That’s why an invoice, a contract or a diploma that “looks authentic” no longer proves anything.
The difference between this and a real one is no longer visible: it’s proven. CODEX adds to every document you issue a cryptographic proof —anchored in Bitcoin, impossible to forge— and turns the absence of proof into the warning sign. The real thing carries proof. What doesn’t, distrust it.
Real recording · unedited
This is the check.
Three seconds.
You drop the PDF. Your browser computes the hash and checks it against the Bitcoin chain. The file never leaves your device, and the answer does not come from us.
Recorded against the live site. You can repeat it right now with any document: check a document →
The diploma you issued six years ago
is still checkable today.
A certificate is worth whatever its verification is worth. If the only way to check it is to phone you, the qualification depends on your phone still being answered a decade from now.
Issue in bulk
A whole graduating class in one go: one holder per line, and every student gets their credential with its own verifiable link.
Employers check it themselves
Whoever is hiring scans the code and sees at once whether the qualification is genuine, whose it is and whether it still stands. No phone call, no sign-up, no trust required.
Revocable, and it shows
If a qualification is annulled, anyone verifying it will see that it was revoked. The correction is public and traceable, not an email someone has to take on faith.
What you won't find anywhere else
What only CODEX does
Your evidence doesn't die with your vendor
Signature platforms keep the evidence on their servers. The day you close the account —or they close— your document is still a PDF, but the proof leaves with them. CODEX's travels inside the file and is anchored in Bitcoin: it doesn't depend on us existing.
Works with your Spanish national eID
Sign the PDF with Autofirma —the official tool— and upload it: CODEX seals it, anchors it and shows your qualified signature. Others force you to use theirs; here the one you already have works.
Proof they received it
Each recipient gets their own link. Opens and confirmations are recorded, and closing generates a sealed dossier that works as evidence. See how
Diplomas checked without calling you
Issue certificates in bulk. Each carries its code and proof, and can be revoked: anyone checking later sees it. See how
It reviews documents and tells you what's missing
Paste a legal notice or a GDPR clause and CODEX checks what the rule requires, citing the article. Six Spanish frameworks. See how
You can prove the issuer is you
Verify your domain once and the "self-declared issuer" notice disappears from all your documents: recipients see the identity is checked, not just the content.
The proof travels inside the document
The PDF carries its hash, its timestamp and a verifier that works offline and without us. Others keep the evidence on their server: if they shut down, your proof goes with them.
Anchored in Bitcoin, not in an authority
The date is confirmed by a public chain neither we nor anyone controls. It doesn't depend on a certificate authority still existing in ten years.
19 legal templates that state when they were reviewed
GDPR, eIDAS, AI Act. Ten cite the specific rule and carry their review date printed inside the document. If they're outdated, you can see it.
Unlimited documents, free too
Everyone charges per envelope sent. Here there's no counter: seal as many as you want. You pay for your brand, your team and AI — not per document.
An AI can check them
Open MCP server: connect your assistant and ask whether a document is authentic. Free, no account, and it works with other issuers' documents too.
Genuinely accessible, and archival
WCAG 2.1 AA with keyboard and screen reader —mandatory since June 2025 and almost nobody complies— and PDF/A-3b validated with veraPDF.
Three things a PDF —or an email, or a WhatsApp— can’t give you.
An email or a WhatsApp counts as evidence in court… until the other side challenges it: a screenshot can be doctored and no one can prove the date. Exactly what CODEX establishes out of the box.
A fingerprint that can’t be touched
Every document has a unique SHA-256. Change one comma and the fingerprint changes. No silent edit gets through.
Anyone checks it, not us
The fingerprint is anchored in Bitcoin. A client, an auditor, a regulator — they verify it in one click. Not even CODEX can rewrite it.
The proof outlives you
It doesn’t live on our servers: it lives on the public chain. If CODEX disappeared tomorrow, your proof would still be valid.
Three steps. Ten seconds of new habit.
You don’t change how you work. You only change the one thing that was broken: how you prove a document is yours and real.
Create or upload your document
Generate a certificate, a contract or terms — or upload the PDF you already have. One click seals it and anchors it in Bitcoin.
Paste the link, not the file
Where the attachment used to go, a live link goes instead. Anyone you choose opens it —no account, no app— and sees the truth of the document.
Anyone checks it, forever
Link or QR: authentic, in force, up to date in one second. And if you need it in court, the evidence is already built.
Bitcoin holds it.
Every sealed document has a SHA-256 fingerprint anchored on the public Bitcoin chain via OpenTimestamps. Scan the QR or open the verification and you get the answer in one second — authentic or not, in force or expired. Download the proof and check it yourself: it depends on neither this page nor us.
It’s admissible electronic evidence: it proves integrity and existence-at-a-date — what an email or a screenshot can’t hold up if someone disputes them. Acceptance is a recognized e-signature — and it maps to your local e-sign law (eIDAS in the EU, ESIGN/UETA in the US, equivalents elsewhere) — with a sealed receipt.
However many you are. It works the same.
The same seal, the same public proof and the same live link — whether used by one person or a network of offices.
Individuals
A private agreement or proof of authorship and date for your work or your idea, with weight against anyone who disputes it. Free to start.
Freelancers and professionals
Invoices, quotes and deliverables your client opens, checks and accepts — impossible to deny later. From €6.99.
SMBs
Contracts, NDAs and terms with your brand, a flat plan for the whole team and compliance acknowledgement with a dossier.
Agencies, firms & platforms
White-label for your whole client base, multi-office in a single account, and the proof your client, a regulator or an auditor accepts.
Let AI fake everything else.
Not yours.
Bring the document you were about to attach —a certificate, a contract, a notice—, seal it and paste the link where the file used to go. No one can forge it, anyone checks in one click that it’s truly yours, and the proof stays there even if we don’t. No trust required.
Received a document and want to know if it is authentic? Check it here —no account, free.