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Hermes Notar — Bitcoin-anchored SHA-256 Timestamping
x402
Hermes Notar — Bitcoin-anchored SHA-256 Timestamping is a paid API for AI agents from notar.185-190-142-134.sslip.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).
Accepts a SHA-256 hash, returns a Nostr-signed receipt and an OpenTimestamps proof anchored to the Bitcoin blockchain as tamper-evident evidence of existence at a point in time.
Price / call$0.005
Success—
StatusUnknown
How this service works
Send a SHA-256 digest of your output. Get an instant Nostr-signed receipt and a Bitcoin-anchored OpenTimestamps proof that anyone can verify without trusting us. Use it as proof of delivery, proof of authorship, or audit trail (e.g. EU AI Act logging).
Output
A JSON object containing: a 'status' field (e.g. 'pending' while Bitcoin confirmation is awaited), a 'receipt' object with a Nostr event (kind 21040, pubkey) providing an instant cryptographic signature, an 'ots_file' URL to download the raw OpenTimestamps proof file, and a 'proof' URL to verify the anchoring — all tied to the submitted hash.
Example use cases
EU AI Act compliance logging
“We just generated an AI decision report — please timestamp its SHA-256 hash 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b3e699c69b7c2e5f6a8b1d2e3 on the Bitcoin blockchain and get a Nostr-signed receipt so we have an immutable audit trail for EU AI Act compliance.”
Proof of authorship before publication
“I've written a whitepaper and computed its SHA-256 digest 3a7bd3e2360a3d29eea436fcfb7e44c735d117c42d1c1835420b6b9942dd4f27 — can you notarize it on Bitcoin using Hermes Notar so I have cryptographic proof I authored it before I publish?”
Proof of delivery for a digital asset
“I just delivered a software build to the client — its SHA-256 hash is b94f6f125179e95a1c11d13e7c49751c23a6c0f4f9b0c6a1e2d3f4a5b6c7d8e. Timestamp and anchor it on Bitcoin so I can prove exactly when delivery happened if there's ever a dispute.”
Technical details
Endpoint
GEThttps://notar.185-190-142-134.sslip.io/x402/stamp?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a trustless, publicly verifiable, decentralized proof that a piece of data existed at a specific moment in time — without disclosing the data itself. It is ideal for AI audit trails (EU AI Act), proof of authorship, proof of delivery, or any compliance scenario requiring a tamper-evident timestamp. Prefer it over centralized notarization services when verifiability without trusting the provider is required, and over manual OpenTimestamps tooling when you need an automated, pay-per-call API with a Nostr-signed instant receipt in addition to the Bitcoin anchor.
Side effects
- Invalid or malformed hash (not 64 hex characters) returns an error — hash must match ^[0-9a-fA-F]{64}$
- Payment not completed via x402 protocol results in HTTP 402 and no receipt
- Bitcoin anchoring is initially 'pending' until the next OTS aggregation and block confirmation — final proof may take hours
- Nostr relay unavailability could delay receipt issuance
- Network timeout on the sslip.io host (IP-based domain, no SLA guarantee)
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"proof": "/proof?hash=...",
"status": "pending",
"receipt": {
"kind": 21040,
"pubkey": "7e801bc29b782a62fe60b4b4760a3f411c88a0ca5852f623aacea96b9fd4e77b"
},
"ots_file": "/proof.ots?hash=..."
}
}Tags
x402
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