# x402helper.xyz URL Notarization Endpoint

> x402helper.xyz URL Notarization Endpoint is a paid API for AI agents from x402helper.xyz, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-31).

Fetches a public URL and returns a cryptographic notarization (hash or full body) anchored on Base (chainId 8453) for $0.009 USDC per call.

## Facts

- Endpoint: GET https://x402helper.xyz/89e509/notarize?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402helper-xyz-url-notarization-endpoint-cbdaae80
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ylmsDtcPXCX3uZ5KbAelu

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 x402helper-xyz-url-notarization-endpoint-cbdaae80
```

Example prompt: Please notarize https://example.com/invoice-2024-06.pdf and give me the SHA-256 hash anchored on Base — just the hash metadata, not the full body.

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-use cryptographic attestation of a public URL's content anchored on Base blockchain. Prefer it over self-managed notarization when you need minimal setup, on-chain proof, and only pay $0.009 per call. Best suited for agents that need tamper-evident records of web content, document snapshots, or pricing/terms pages.

## Known failure modes

- URL is unreachable or returns a non-200 status — notarization fails with an error result
- Private or non-public URL passed — fetch is blocked
- Payment (USDC via x402) not included or insufficient — HTTP 402 returned before processing
- Invalid mode enum value — request rejected at schema validation
- URL parameter missing — required field error

## How this service works

X402 micropayments server — AI agents pay USDC for OFAC screening, rates, and billing verification.

## Output

A JSON object with a success flag and a result object containing the notarization data: SHA-256 hash of the fetched URL content, metadata about the fetch (timestamp, URL, HTTP status), and optionally the full base64-encoded response body if mode=full. The attestation is anchored on Base (chainId 8453).

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "default": null,
       "description": "Public http(s) URL to fetch and notarize"
      },
      "mode": {
       "enum": [
        "hash",
        "full"
       ],
       "type": "string",
       "default": null,
       "description": "hash = metadata + sha256 only (default); full = also return the fetched body (base64)"
      },
      "network": {
       "type": "string",
       "default": null,
       "description": "Reserved (attestations are chainId 8453 / Base)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {},
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402helper-xyz-url-notarization-endpoint-cbdaae80/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402helper.xyz](https://www.zero.xyz/host/x402helper.xyz/llms.txt)