# PayAI URL Notarization & Cryptographic Attestation

> PayAI URL Notarization & Cryptographic Attestation is a paid API for AI agents from payai.agentstools.dev, paid per call via x402, $0.008/call, status unknown (last checked 2026-10-11).

Fetches a public URL server-side and returns a signed snapshot with EIP-712 and EAS off-chain cryptographic attestations proving the URL's content, hash, and timestamp at fetch time.

## Facts

- Endpoint: GET https://payai.agentstools.dev/notarize?utm_source=zero.xyz
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/payai-url-notarization-cryptographic-attestation-3ce6607c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JbXiFj4Lfx7IT8cGNQYmM

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 payai-url-notarization-cryptographic-attestation-3ce6607c
```

Example prompt: Can you notarize the URL https://example.com/report.pdf right now — just give me the metadata and SHA-256 hash without the full body — and return a cryptographic EAS attestation proving what that URL contained at fetch time?

## When to prefer this

Use this endpoint when you need cryptographic, non-repudiable proof of what a public URL contained at a specific moment in time — particularly when EIP-712 signatures or EAS off-chain attestations on Base (chainId 8453) are required. Prefer it over simple HTTP fetching when integrity verification, timestamping, or blockchain-verifiable attestations are needed for legal, compliance, audit, or trust-verification purposes.

## Known failure modes

- URL is not publicly accessible or returns a non-200 status — attestation reflects the actual HTTP status observed
- URL requires authentication or is behind a firewall — fetch fails, no attestation produced
- Invalid or malformed URL input — request rejected with validation error
- Upstream server times out — fetch fails, error returned
- mode parameter not recognized — defaults to hash mode

## How this service works

Notarize a public URL: we fetch it ourselves and return a signed snapshot (final URL, HTTP status, content-type, sha256 of the body, server timestamp, upstream host) with TWO cryptographic attestations — a plain EIP-712 signature and an EAS off-chain (Version2) attestation. Proves what this endpoint observed at fetch time (integrity + timestamp + non-repudiation). mode=hash (default) returns metadata + hash only; mode=full also returns the body.

## Output

Returns a signed snapshot including the final resolved URL, HTTP status code, content-type header, SHA-256 hash of the response body, a server-side timestamp, the upstream host, an EIP-712 signature, and an EAS off-chain (Version2) attestation. If mode=full is specified, also includes the base64-encoded response body.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "Public http(s) URL to fetch and notarize"
      },
      "mode": {
       "enum": [
        "hash",
        "full"
       ],
       "type": "string",
       "description": "hash = metadata + sha256 only (default); full = also return the fetched body (base64)"
      },
      "network": {
       "type": "string",
       "description": "Reserved (attestations are chainId 8453 / Base)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/payai-url-notarization-cryptographic-attestation-3ce6607c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payai.agentstools.dev](https://www.zero.xyz/host/payai.agentstools.dev/llms.txt)