Sealed now. Provable later.
Some records only matter when the time comes: a will, an embargoed report, a whistleblower archive, a priority claim held back until it is needed. The doubt that greets them is always the same, was this changed after the fact? Seal the document today by notarizing its fingerprint with a neutral witness. You keep the original. When it is revealed, anyone can confirm the revealed version is byte-identical to the one sealed, and that the seal carries a timestamp from before the reveal. Append-only plus time, so a promise can outlast the person who made it.
Promises that must survive their makers.
A will or letter of wishes
Prove the version read out later is exactly the one written today, unchanged, without lodging the document itself with anyone. Evidence beside a properly executed will, never a replacement for one.
Embargoed work
A report, an audit finding, an investigation. Seal it now so that when the embargo lifts, no one can claim it was edited to fit what happened in between.
A whistleblower archive
Fix the record of what you held, and when, before disclosing it. The seal shows the archive predates the retaliation, without exposing its contents early.
A priority claim
Hold an invention or design in confidence while proving the date you had it, revealing only if and when a dispute makes it necessary. See also priority proof.
Seal a document, in your browser.
Pick the document to seal. Your browser computes its SHA-256 fingerprint locally with the Web Crypto API. The document is hashed in your browser and never uploaded. We witness only the fingerprint, never the contents, and we never hold or reveal your document. Nothing is stored about you.
seal record (JSON)
curl -X POST https://dynamicfeed.ai/v1/notarize -H "content-type: application/json" -H "X-API-Key: YOUR_FREE_KEY" -d '{"payload_sha256":"<your hash>","subject":"sealed-<your-label>"}'
The returned receipt is Ed25519-signed and RFC 3161 timestampable. Store the receipt where the person who will reveal the record can find it, alongside the original document. Re-verify any time against /.well-known/keys or with the MIT-licensed verifiers (see /verify). A free key is self-serve at POST /signup, details in the docs.
When the time comes, prove it is unchanged.
Whoever reveals the record drops the original document and pastes the receipt that was saved with it. The browser re-hashes the document and confirms it is byte-identical to what was sealed, and shows the seal's timestamp. This runs entirely in the browser: neither the document nor the receipt is uploaded.
A match proves the revealed document is exactly the bytes sealed on the receipt's date. To also confirm the receipt is genuine and its timestamp intact, check its signature at /verify.
A witness that cannot quietly change its mind.
The seal is a fingerprint of the document, signed at the moment and independently time-stamped by an accredited authority, then kept in an append-only archive. Because the timestamp comes from a party that is not us and cannot be back-dated, and because the fingerprint changes if a single byte of the document changes, a record revealed years later either matches the seal or it does not. There is no room to argue the version was quietly adjusted to suit later events. Our records work against every party equally: anyone can re-check them, which is exactly what makes a sealed record worth sealing.
Evidence about a document, not the document's keeper.
Dynamic Feed is a neutral witness, not a lawyer, executor, escrow agent or court. A sealed record proves a document existed in a specific form on a date and has not changed since. It is not a legal will and does not make any document a valid will: wills and similar instruments have formal execution requirements that vary by country and are satisfied only by following them with proper advice. We do not hold, store, release or reveal your document, we do not decide when anything is revealed, and we are never the money path. What we hold is a fingerprint and a signed timestamp. Use a sealed record as corroborating evidence beside a properly made will, agreement or disclosure, with advice from a qualified professional. Advisory evidence, tamper-evident not tamper-proof, not a certification and not legal advice.
Seal it once. Prove it forever.
One call seals a fingerprint; a keyless check reveals the match. The document stays with you the whole time.