Sellat for systems
Protect files at scale without sending the originals to Sellat. Your system calculates the SHA-256 fingerprint and sends it through the API; Sellat creates the proof and exposes its status.
How it works
The original file never leaves your infrastructure. Only its SHA-256 is sent.
One authenticated call with a label and whatever metadata you need.
The response is immediate: your application does not wait for a blockchain transaction.
Each proof has its own identifier you can use to look up its state.
Multilayered timestamp
Every fingerprint is protected by layers that verify separately. If one layer disappeared, the rest still stand: none of them depends on Sellat.
Proof identifier, as soon as the API accepts the fingerprint.
An individual, portable proof (proof.json) inside the batch tree.
The batch root, anchored in a public transaction.
A free attestation with the open standard, on the most established chain.
The model supports additional layers per batch when your case needs them.
Each layer verifies independently, without trusting Sellat.
Asynchronous acceptance, honest status.
The API responds 201 and the proof enters as `queued`. The status reflects what Sellat actually knows at each moment: a transaction whose outcome has not been checked is never shown as confirmed.
It proves
The Sellat API proves that an exact file existed on a specific date. It does not publish the file, reveal its content, or replace a notary. It registers a verifiable digital fingerprint that can be used to check the file’s integrity in the future.
Add proof of existence to contracts, claims, or sensitive documentation.
Certify photos, reports, damage, or evidence before a claim.
Register critical document versions without publishing the content.
Seal deliveries, site progress, incidents, or inspection photos.
Add a traceability layer to internal processes with attached files.
Let users register evidence before mediation, delivery, or a claim.
Frequently asked questions
Yes. Any Sellat account can create an API key from its dashboard: 10 proofs a day on the free account and 5,000 on the Pro account. For more volume or your own terms, write to us.
No. Through the API you only send the SHA-256 fingerprint: the file never leaves your system and Sellat never receives it. If you want Sellat to keep the original, you can deposit it separately, in custody.
Yes. The API is designed for products and internal tools that need to add verifiable proof of existence to attached files.
No. It generates technical proof of existence with date, hash, and a verifiable link, but it does not replace legal advice.
It depends on the mode. In the normal flow the file is uploaded to Sellat only to calculate its SHA-256 fingerprint and prepare the proof; afterwards it is not retained. With a free account, Sellat Local calculates the fingerprint on your own device and the original is never uploaded. And if you turn on custody — optional, and only with an account — Sellat does keep the original, checked against its fingerprint, until you remove it. In all three cases the only thing in the public record is the hash, a code that cannot be used to read or rebuild the content.
Create a key from your dashboard and start today. If your product needs more volume or its own terms, write to [email protected].
