# DataSieve Receipt Notarization

> DataSieve Receipt Notarization is a paid API for AI agents from api.datasieve.xyz, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Cryptographically notarizes an arbitrary JSON claim by returning a signed Ed25519 receipt attesting to the content hash and timestamp at the moment of receipt.

## Facts

- Endpoint: POST https://api.datasieve.xyz/receipts/notarize
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/datasieve-receipt-notarization-b486e2ac
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_o0QF5r5YCBZwpq38j7Kei

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability datasieve-receipt-notarization-b486e2ac -d '<json body>'
```

Example prompt: Notarize this JSON claim for me — {"invoiceId":"INV-2024-881","amount":420.00,"currency":"USD","approvedBy":"agent-7"} — and label it 'nightly-invoice-agent' so I have a signed timestamp receipt I can verify later.

## When to prefer this

Choose this endpoint when you need a lightweight, serverless-friendly, pay-per-call cryptographic timestamp on arbitrary JSON without account setup or data retention by a third party. Ideal for ephemeral AI agents that need tamper-evident audit trails, pre-deadline proof of existence, or multi-agent coordination receipts. Prefer this over blockchain anchoring when low cost ($0.005 USDC), low latency, and no stored-data guarantees are the priority. Not suitable if you need the data itself to be stored or retrievable from DataSieve.

## Known failure modes

- Malformed or non-JSON claim body returns a 400-level error
- Missing required 'claim' field results in validation failure
- Label exceeding 120 characters is rejected
- Payment not completed or invalid x402 payment header causes a 402 Payment Required response
- Network timeout during Ed25519 signing returns a 5xx error
- Duplicate submission of the same claim at a different time produces a different signature due to different receivedAt timestamp

## How this service works

Standing infrastructure for ephemeral AI agents, paid per call over x402. Watches, dead-man switches, and multi-agent coordination. No account; wallet as identity.

## Output

A JSON object containing a verification URL and a signed receipt. The receipt includes the Ed25519 algorithm identifier, a base64url signature, a key ID, and a statement object specifying protocol version, kind ('notarized-claim'), what is attested (receipt time and content hash only — not the original data), the service name, the Unix millisecond timestamp of receipt, the SHA-256 hash of the canonicalized claim, and the claimant label you supplied. The original claim is never stored by DataSieve.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "description": "Any JSON. Hashed with sorted-key canonical JSON and signed; never stored, so keep your copy."
  },
  "label": {
   "type": "string",
   "maxLength": 120,
   "description": "Your own label, echoed into the signed statement as claimantLabel — it is your text, not a DataSieve assertion"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "verify": "https://api.datasieve.xyz/receipts/verify",
  "receipt": {
   "alg": "ed25519",
   "sig": "base64url…",
   "keyId": "9f2c…",
   "statement": {
    "v": 1,
    "kind": "notarized-claim",
    "attests": "receipt-time-and-content-hash-only",
    "service": "datasieve",
    "receivedAt": 1786713600000,
    "claimSha256": "b1946ac9…",
    "claimantLabel": "nightly-invoice-agent"
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/datasieve-receipt-notarization-b486e2ac/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.datasieve.xyz](https://www.zero.xyz/host/api.datasieve.xyz/llms.txt)