Mercury · Cited Metadata

Extract$0.006 / callLivex402API key

GET /buy/metadata

What it does

URL → one typed, SIGNED metadata record (JSON-LD + OpenGraph + Twitter-card + standard <meta> + canonical + title), by source. Deterministic, keyless, no LLM — the social-card/SEO/schema.org record an agent can PROVE.

The goal it serves: turn a page into a typed record an agent can act on, with the signed receipt proving the fields are exactly what Mercury resolved from the source — deterministic, keyless, no LLM.

Schemas & output preview

Input schema — the exact request shape the route validates.

json · input schema

{
  "type": "object",
  "properties": {
    "url": {
      "type": "string",
      "maxLength": 2048,
      "description": "the page to read metadata from (http/https)"
    }
  },
  "required": [
    "url"
  ],
  "additionalProperties": false
}

Output schema — the exact response shape the handler returns.

json · output schema

{
  "type": "object",
  "properties": {
    "ok": {
      "type": "boolean",
      "description": "true on success; false on an honest failure (you are NOT charged for ok:false)"
    },
    "url": {
      "type": "string",
      "description": "final URL after redirects"
    },
    "status": {
      "type": "integer",
      "description": "upstream HTTP status"
    },
    "fetchedAt": {
      "type": "string",
      "description": "ISO-8601 time the page was read"
    },
    "data": {
      "type": "object",
      "description": "the typed metadata record, by source",
      "properties": {
        "title": {
          "type": [
            "string",
            "null"
          ],
          "description": "<title> text"
        },
        "canonical": {
          "type": [
            "string",
            "null"
          ],
          "description": "<link rel=canonical> href"
        },
        "openGraph": {
          "type": "object",
          "description": "all og:* / article:* / product:* meta, keyed by FULL property name (e.g. 'og:title')",
          "additionalProperties": {
            "type": "string"
          }
        },
        "twitter": {
          "type": "object",
          "description": "all twitter:* card meta",
          "additionalProperties": {
            "type": "string"
          }
        },
        "standard": {
          "type": "object",
          "description": "standard head meta (description, author, robots, viewport, charset, keywords, …)",
          "additionalProperties": {
            "type": "string"
          }
        },
        "jsonLd": {
          "type": "array",
          "description": "every parsed JSON-LD block (@graph flattened)",
          "items": {
            "type": "object"
          }
        },
        "counts": {
          "type": "object",
          "description": "how many signals of each class were found",
          "properties": {
            "jsonLd": {
              "type": "integer"
            },
            "openGraph": {
              "type": "integer"
            },
            "twitter": {
              "type": "integer"
            },
            "standard": {
              "type": "integer"
            }
          }
        }
      }
    },
    "text": {
      "type": "string",
      "description": "the canonical signed string: JSON.stringify(data, sortedKeys). The attestation signs THIS."
    },
    "error": {
      "type": "string",
      "description": "present only when ok:false"
    },
    "attestation": {
      "type": "object",
      "description": "EIP-191 provenance receipt over sha256(text)+url+status+time, verifiable OFFLINE by anyone (key pinned at /.well-known/mercury-attestation). Proves THIS metadata record is exactly what MERCURY parsed from THIS url at THIS time — the wedge a free metadata API cannot emit."
    }
  },
  "required": [
    "ok",
    "url"
  ],
  "additionalProperties": false
}

Output preview — a real example response, shown free (you only pay when you call the route).

json · output preview

{
  "ok": true,
  "url": "https://example.com/",
  "status": 200,
  "fetchedAt": "2026-06-04T00:00:00.000Z",
  "data": {
    "title": "Example Domain",
    "canonical": null,
    "openGraph": {},
    "twitter": {},
    "standard": {
      "viewport": "width=device-width, initial-scale=1"
    },
    "jsonLd": [],
    "counts": {
      "jsonLd": 0,
      "openGraph": 0,
      "twitter": 0,
      "standard": 1
    }
  },
  "text": "{\"canonical\":null,\"counts\":{\"jsonLd\":0,\"openGraph\":0,\"standard\":1,\"twitter\":0},\"jsonLd\":[],\"openGraph\":{},\"standard\":{\"viewport\":\"width=device-width, initial-scale=1\"},\"title\":\"Example Domain\",\"twitter\":{}}"
}

Pay & call

Your agent calls the route; the 402 challenge carries the exact price ($0.006, USDC on Base mainnet); the x402 client settles via the CDP facilitator and retries. No key, no signup.

agent.mjs · x402

import { wrapFetchWithPayment } from "x402-fetch";
const pay = wrapFetchWithPayment(fetch, account); // viem account holding a little USDC on Base
const res = await pay("https://network.mercury-hq.com/buy/metadata?url=https://example.com");
const out = await res.json(); // the result + `attestation` (the signed receipt)

Prepaid alternative — the same route accepts an API key:

bash · API key

# Same route, prepaid API-key rail (Bearer mk_live_…) — get a key at https://network.mercury-hq.com/developers
curl -H "Authorization: Bearer mk_live_YOURKEY" "https://network.mercury-hq.com/buy/metadata?url=https://example.com"

Pay over 402 — get the missing pieceEvery paid call returns an EIP-191 signed receipt — verify it free at /x402/verify.

Verify the receipt

Recover the EIP-191 signature over sha256(content)‖url‖status‖fetchedAt‖nonce and confirm the signer equals the pinned attestation key 0xACB40253BD71Bb9a5d491b2c6EFF755F2A33Fc75 (published at /.well-known/mercury-attestation). No callback to Mercury — the receipt verifies offline, forever. Verification is always free: POST the receipt to /x402/verify or run ecrecover yourself.

Fact	Value
Attestation signer (pinned)	`0xACB40253BD71Bb9a5d491b2c6EFF755F2A33Fc75`
Key published at	/.well-known/mercury-attestation
Live verifier (free)	/x402/verify
Settlement	real USDC on Base mainnet (eip155:8453) via CDP — auditable on BaseScan

Cited Feed

$0.005

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Cited Links

$0.005

URL → a SIGNED outbound/internal link graph: every <a href> as an absolute URL + anchor text, classified internal vs external against the page…

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Cited Table

$0.006

URL in → the page's main HTML <table>(s) parsed into typed, header-keyed rows (JSON) + clean RFC-4180 CSV, with a signed provenance receipt over the…

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Structured Extract

$0.004

TYPED structured extract for autonomous agents — URL + schema → a clean, type-safe JSON record. Where /buy/fetch returns page TEXT (and ?extract=…

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More: all services · /catalog · the headline web-fetch · agent twin of this page: GET /university/docs/cited-metadata?format=md

Mercury · Cited Metadata

What it does

Schemas & output preview

Pay & call

Verify the receipt

Related

Cited Feed

Cited Links

Cited Table

Structured Extract