AI can fake any document now.
Not yours.
Documents nobody can forge and anyone can check. Instead of attaching a file, you send a link.
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 →
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.
The tool everyone uses.
With the proof none of them give you.
Signing and sending documents electronically is the norm — you do it every day with the usual tools. But they all share the same blind spot —and AI just made it urgent—: the proof that the document is authentic lives on their server. If they vanish, change their policy, or no one opens their platform, you’re left with nothing. CODEX is just as easy to use — and the proof lives in Bitcoin: public, perpetual and verifiable by anyone without trusting anyone, not even us.
The top legal tier (what the EU calls “qualified”, QES) almost no one uses —and those platforms charge €3 to €6 per signature for it— isn’t what drives daily work. Simple e-signatures are. On that ground, everyone’s ground, CODEX isn’t behind: it’s ahead on the one thing that matters when there’s a dispute — being able to prove it.
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.
Your name, impossible to impersonate.
It’s not enough that the paper can’t be touched: you need to know who issues it. CODEX makes it clear right in the verification — and protects your brand from anyone trying to ride on it.
Verified issuer
You prove you control your domain and the page shows it: “verified · controls acme.com”, not just any name anyone could type in.
Official body, no argument
A .gov, .edu domain — or your country’s official equivalent — can’t be impersonated — so controlling it proves real identity. The verification flags it separately.
And if someone abuses your name
Anyone can report a fake document from the verification, and an issuer who abuses it is flagged for all to see.
A document that updates and talks back.
Being impossible to forge is the baseline. On top of that, every CODEX document is live: a PDF froze, mute, the day you sent it; this one doesn’t.
Always the latest version
You fix something and every link already sent shows the new version. The link doesn’t change; the content does.
Every open, logged
You know who opened it, when and how many times — not a “I sent it and we’ll see”.
Accept, decline, negotiate
An accept button with a sealed receipt. On a quote, the client can even re-price and counter-offer right in the link.
Acknowledgement for compliance
Distribute a policy or a privacy notice to a list, chase whoever’s missing and keep the evidence dossier a regulator or auditor accepts.
Explicit expiry
“In force until 31/12” in plain sight. Expired = clear warning and acceptance blocked.
Live badge + QR
Embed the seal on your site updating itself, and take the verification to paper with a QR.
Invoices and quotes · certificates and diplomas · contracts and NDAs · agreements between individuals · terms of sale · policies with acknowledgement · privacy notices · proof of authorship and date… all are sealed, proven and responded to the same way.
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.
Not an anonymous startup. It's the software arm of a European manufacturer.
CODEX is built by AIM, the software division of Biomag: a European company with its own brands on the market and years shipping product. Not a weekend crypto experiment — engineering already running in production, aimed at a new problem. We built CODEX because AI has made forging any document trivial, and a legacy signature proves who signs, but not that the document hasn't been altered or that it existed on a given date. Anchoring the proof in Bitcoin solves it: verifiable by anyone, forever, without depending on us.
Real platform figures, aggregated and with nobody’s data in them. And if you would rather not take a number of ours on faith: check a document yourself — no account, no permission, no dependency on us.
Unlimited documents. Free, forever.
Signature platforms cap your documents, or charge per person to remove the counter. €45 per user to remove the cap.
Here there is no counter. Seal as many as you want, today and in ten years, without paying anything.
Charging per seat punishes whoever shares most. Here you pay for the plan, not for each person who opens the link — adding people never raises the price. And no lock-in: pay monthly and cancel whenever, or go yearly and save 33%.
What everyone wants to know.
How is it different from DocuSign or Adobe?
Day to day, what you use on them is a simple signature — the same legal level as CODEX. The difference is the proof: theirs lives on their server and you verify it by opening the file in their software; CODEX’s lives in Bitcoin, anyone checks it with a link and it keeps holding even if CODEX disappears. The top legal tier (the EU’s “qualified”/QES) almost no one uses and is paid separately; if you ever need it, it integrates on demand.
Does it have legal validity?
It’s admissible electronic evidence: it proves integrity and existence-at-a-date. Acceptance is a recognized simple e-signature (eIDAS in the EU, ESIGN/UETA in the US, local equivalents elsewhere), with a sealed receipt: exact version, date, IP and agent. Sturdier than an email or a WhatsApp, which get challenged precisely for proving neither integrity nor date.
What’s this “anchored in Bitcoin” thing?
Each document’s seal is anchored via OpenTimestamps on the Bitcoin chain: a proof of existence and integrity that not even we can alter. You don’t need to know anything about crypto — just that your proof doesn’t depend on trusting anyone.
Is it valid for long-term legal archiving?
Yes. The PDF CODEX issues is PDF/A-3b compliant (ISO 19005-3), the archival format required by public bodies, courts and regulated sectors — the same one used by European e-invoicing. You can check it yourself with veraPDF, the industry's official validator: no need to take our word for it. And unlike a plain PDF/A, ours carries the integrity proof inside: sealed content, Bitcoin anchor and a verifier that works offline.
Can an AI check my documents?
Yes, and without an account. CODEX publishes an open MCP server at aim-codex.ai/mcp: add it as a connector in Claude, ChatGPT or any compatible client, and the assistant can check whether a document has been altered against Bitcoin.
It works with documents from any issuer, not just ours. And before giving a verdict, the tool states what a seal does not prove: integrity and time, not identity nor that anyone committed to anything.
What legal weight does this carry in the EU?
The European eIDAS Regulation states it in Article 46: "An electronic document shall not be denied legal effect and admissibility as evidence in legal proceedings solely on the grounds that it is in electronic form". Article 25.1 says the same for signatures, even non-qualified ones.
In practice: your document is admissible, and its strength depends on the evidence behind it. That is what CODEX adds: sealed content, an RFC 3161 timestamp, a Bitcoin anchor and a verifier that works without us.
What CODEX is not: we are not a qualified trust service provider (QTSP) and we do not issue qualified electronic signatures, the only kind equivalent to a handwritten one (eIDAS art. 25.2). If your procedure requires a qualified signature, you need a QTSP. CODEX proves integrity and existence in time, not the issuer's legal identity.
Is my data mine?
Yes. Your data is hosted in the EU (Amsterdam, Netherlands) — out of reach of US extraterritorial law (e.g. the CLOUD Act) that US-based providers are subject to. Export the evidence log (CSV) and your whole CODEX (ZIP) whenever you want. No data hostage-taking.
What documents is it for?
Invoices and quotes, certificates and diplomas, contracts and NDAs, agreements between individuals, terms of sale, internal policies with acknowledgement, privacy notices and proof of authorship and date. Generate the document or upload the one you have: it all travels as a live link and, if you want, is accepted right there.
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.