Data notarization API: proof in one POST.
Send bytes — or only their hash — and get back a signed witness record plus a public log entry anyone can verify forever; the log head is anchored to Bitcoin daily. US$49 a month for 10,000 notarizations during beta, and you can try it on a free key's quota first.
The call
Free key to start; self-serve checkout at /notary when you're ready. Every record is Ed25519-signed and lands in the public transparency log above.
# notarize a reading from YOUR feed (free key: POST /signup)
curl -X POST https://dynamicfeed.ai/v1/notarize -H "X-API-Key: $KEY" \
-H "content-type: application/json" \
-d '{"payload": {"sensor": "rain_gauge_7", "mm": 18.4}, "subject": "Acme Sensors"}'
# private mode — we never see your data, only its sha256
curl -X POST https://dynamicfeed.ai/v1/notarize -H "X-API-Key: $KEY" \
-d '{"payload_sha256": "", "subject": "Acme Sensors"}' Sample response
{ "schema": "notary/v1", "issuer": "dynamicfeed.ai",
"witnessed_at": "2026-06-10T09:27:32+00:00", "mode": "payload",
"payload_sha256": "e9e325a2…", "subject": "Acme Sensors Pty Ltd",
"signature": { "alg": "Ed25519", "key_id": "df-ed25519-…" } }Why live data
When a customer, auditor or insurer asks what your feed said at 09:41 on March 3rd, pointing at your own database proves nothing — you control it. A notarization is a neutral third party's signed witness record: these exact bytes existed at this moment, logged in a public, append-only hash chain whose head is timestamped on Bitcoin. Building that yourself means key management, canonicalization, transparency logging and blockchain anchoring; here it's one POST, with open verifiers in Python, JavaScript and Rust so your customers can check records without an account. US$49/month is less than an hour of the engineer who'd otherwise build it.
Use it for
- Sensor and IoT feeds that end up as evidence in disputes and claims
- Price and market feeds whose history gets argued about
- Research datasets with reproducibility requirements
- AI systems recording exactly what data they acted on (see the EU AI Act page)
FAQ
What does it cost?
The Notary plan is US$49/month for 10,000 notarizations during beta — including hash-only and BYO-key modes, the public transparency log and up to 3 continuous feeds; US$490/year gets two months free. Notarizations also work on any plan's normal call quota, so you can try it on a free key first. Self-serve checkout at /notary.
What does a notarization attest?
That Dynamic Feed witnessed these exact bytes (or this hash) at witnessed_at — not that the content is true. That honest line is printed inside every record we sign.
Do you see my data?
Only in payload mode. In hash-only mode you send a sha256 and we witness the hash — your bytes never leave your infrastructure.
How do my customers verify a record?
The Ed25519 signature checks against /.well-known/keys with the public recipe at /standard, and any entry has an inclusion proof up to the Bitcoin-anchored log head — no account, no trust in us required.
Can it run automatically?
Yes — register a feed URL and an interval (POST /v1/notary/feeds) and every change is fetched and notarized into the public log: a standing, tamper-evident history of what you published.