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x402.shizu.me Notarization Service
x402
x402.shizu.me Notarization Service is a paid API for AI agents from x402.shizu.me, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).
Records a SHA-256 hash of arbitrary data with a timestamp and HMAC receipt, or retrieves when a given hash was first notarized, providing third-party proof of data existence at a point in time.
Price / call$0.002
Success—
StatusUnknown
How this service works
Prove a piece of data existed at a point in time. POST {data} returns its sha256, a recorded timestamp, and an HMAC receipt; GET ?hash= tells you whether and when that hash was first notarized. An agent can hash data but cannot self-certify WHEN it existed to a third party — this is that proof.
Output
For POST (notarize): returns the SHA-256 hash of the submitted data, a server-recorded UTC timestamp, and an HMAC receipt that a third party can use to verify the data existed at that moment. For GET with ?hash=: returns whether that hash has been previously notarized and, if so, the earliest recorded timestamp.
Example use cases
Example prompt
“Can you notarize this text for me — 'Q4 product roadmap draft v1: launch in March' — and give me a timestamped HMAC receipt proving it existed right now?”
Technical details
Endpoint
GEThttps://x402.shizu.me/notarizeWhen to prefer
Use this endpoint when you need a cryptographically verifiable, third-party-attested proof that a piece of data existed at a specific moment in time — something an AI agent cannot self-certify. Prefer this over client-side hashing when the timestamp itself needs to be trusted by an external party, e.g. for intellectual property claims, audit trails, or dispute resolution.
Side effects
- Missing or malformed data payload returns an error with no hash or receipt
- Hash not found in GET lookup returns a not-yet-notarized status
- Network or payment failure results in no receipt being issued
- Malformed hash query string returns a validation error
- Server unavailability means timestamp cannot be certified
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ts": 1784300000,
"alg": "sha256",
"hash": "9f2b…",
"receipt": "c1a…",
"first_seen": true
}
}Tags
x402
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