How to show your certificate to a client or label

To show your certificate to a client, label, publisher or employer, send the certificate PDF together with the exact file it covers, and point them to the verification link printed under the QR code. They scan the code or open the link, see that the certificate exists and when it was issued, and can drop your file onto the StampR verification page to check it is the same file. Nothing to install, no account needed on their side.

What to send

Your certificate is a PDF. It shows your name, the file name and size, your description of the work, the file's fingerprint, the date and time of the qualified timestamp, the fact that you declared yourself the author, and a QR code that leads to a public verification page. The date comes from BORICA B-Trust, an EU-supervised trust provider, and EU courts presume it accurate.

Send one of these:

• The PDF and the file itself. The usual choice when you are delivering work anyway: a design to a client, a manuscript to a publisher, a track to a label. The other side gets both pieces and can check one against the other.
• Only the verification link or the certificate number. Useful in a portfolio, a CV or an application form, when you just want to show that a dated record exists. The link is printed on the PDF under the QR code.
• The PDF only. Fine when the other person already has the file from you, for example a client who received the final design last week.

One practical rule: send the exact file you certified. If the file is re-exported, resized, compressed by a messenger app or converted to another format, it is a different file as far as the check is concerned, even if it looks identical. Email attachments and download links keep files unchanged; chat apps often do not.

What the other person sees

When someone scans the QR code or opens the link, they land on StampR's verification page for that certificate. What appears there depends on one choice you made when you issued it: whether the certificate is public or private. That choice is made at issuance and cannot be switched later.

A private certificate is not a weaker one. Only your personal details and the description stay hidden. That is why you send the PDF along with it: the PDF carries your name and the description, and the verification page confirms the numbers on it are real.

How they can check that your file is the certified one

Every file has a fingerprint: a long string of letters and numbers calculated from its contents, which changes completely if even one character or pixel changes. Your certificate records the fingerprint of your file at the moment it was certified.

The other person can check it in about a minute:

1. Open stampr.eu/hash_search.
2. Choose the option to check a file, and drop in the file you sent them.
3. The page calculates the file's fingerprint right there in their browser. The file is not uploaded anywhere.
4. If a certificate exists for that exact file, the page says so and shows its timestamp and certificate number. They compare that number with the one on your PDF.

If the numbers match, they know the file in front of them is the same file that existed on the certified date, unchanged since.

A short message you can copy

Keep it calm and factual. This works for clients, publishers and labels alike:

Hi [name], attached is [the final design / the manuscript / the track], together with a certificate that records the date this exact file existed. If you ever want to check it, scan the QR code on the certificate or drop the file onto stampr.eu/hash_search – the fingerprint should match. Nothing needed from your side, it's just part of how I document my work. Looking forward to hearing from you.

For a job application, one line in your portfolio or CV is enough: "Selected works are documented with dated certificates; verification links on request." Then share the link if someone asks.

When not to send it

A certificate is quiet evidence. It works best when it is simply there, not when it is waved around.

• Not as a warning in a first pitch. Opening a demo submission or a cold email with "this is certified, so don't steal it" reads as distrust. You want them listening to the music or reading the pages, not wondering why you expect trouble.
• Not as a threat in a disagreement. If a client is late with payment or a collaborator remembers things differently, start with a normal conversation. Sending a certificate in the first message turns a misunderstanding into a dispute.
• Not when the file is confidential. If you send the PDF, the other side sees the file name and your description. Check both before sharing anything about unreleased or confidential work.

Where it does help: when you hand over final files, when you agree on who owns what, and when a real dispute starts and you need to show which version existed first.

Honest limits

• It shows that this exact file existed at a certain moment, unchanged since, and that you declared yourself its author.
• It does not create or record any rights. Copyright arises automatically when you create a work, and most countries, Germany and Bulgaria included, have no register of works. The certificate isn't an entry in any public register.
• It does not decide who owns the work if there is a dispute, and it does not show whether a work was made by a person or with AI.
• It covers the file, not ideas, concepts or titles.
• StampR is not the trust provider; BORICA B-Trust issues the qualified timestamp. Under Article 41 of the EU eIDAS Regulation, that timestamp is presumed accurate as to its date and the integrity of the data, and it is recognised in all EU member states.

What shows how a work was made is your process: drafts, raw files, project files and sketches. The certificate pins the date; your process fills in the story.

Certify your next file before you send it – the first certificate on an account is €4.90.

Related reading

• Sending a demo to a label – what to do before you hit send.
• What a declaration of authorship is – the statement your certificate carries.
• A client used my design and didn't pay – when a certificate actually comes out of the drawer.
• Do timestamp certificates hold up in court? – what the law says about the date.

Frequently asked questions

Does the other person need a StampR account to check my certificate?

No. Anyone can scan the QR code or open stampr.eu/hash_search and search by certificate number, serial number or fingerprint, or drop in the file itself. No account, no installation.

What does someone see if my certificate is private?

They see that the certificate exists and is valid, with its certificate number, serial number, fingerprint and timestamp, plus a note that the holder kept it private. Your name, the file name and the description are not shown, which is why you send the PDF alongside.

Can I make a private certificate public later?

No. Public or private is chosen when the certificate is issued and stays that way. If you expect to share a work openly, decide before you certify it.

Is my file uploaded when someone checks it on the verification page?

No. The fingerprint is calculated in their browser and only that fingerprint is looked up. The file stays on their device.

Why does the check say no certificate was found for my file?

Almost always because the file is not byte-for-byte the one you certified: it was re-exported, resized, converted or compressed by a messenger app. Send the original file you certified, by email attachment or a download link.

Should I mention the certificate when I first pitch my work?

Usually not. In a first pitch it can read as distrust. Keep it ready and bring it up when you hand over final files, agree on rights, or if someone asks how you document your work.