NFT metadata lookup

Resolve the metadata for a single NFT: title, description, image URLs (original + cached CDN), attributes/traits, and the standard (ERC-721 vs ERC-1155). Send POST /api/nft-metadata with the required fields contract and tokenId and pay $0.001 per call over x402 or MPP (there is no free tier). It returns a JSON object with contract, tokenId, network, title, collection and 4 more.

Useful when you have a contract+tokenId and need the display data without re-fetching the whole collection.

Category: Crypto & onchain data · Tags: crypto nft metadata erc721 erc1155 evm

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/nft-metadata \
  -H "Content-Type: application/json" \
  -d '{"contract":"0xed5af388653567af2f388e6224dc7c4b3241c544","tokenId":"1","network":"ethereum"}'

Without payment this returns HTTP 402 Payment Required with the exact price for nft-metadata; any x402 v2 or MPP client pays it and retries.

Example response

{
  "contract": "0xed5af388653567af2f388e6224dc7c4b3241c544",
  "tokenId": "1",
  "network": "ethereum",
  "title": "Azuki #1",
  "collection": "Azuki",
  "standard": "ERC721",
  "description": "Azuki starts with…",
  "image": "https://example.com/azuki1.png",
  "attributes": [
    {
      "trait_type": "Hair",
      "value": "Pink Hairband"
    }
  ]
}

From an MCP client

catalog.call {
  "slug": "nft-metadata",
  "params": {
    "contract": "0xed5af388653567af2f388e6224dc7c4b3241c544",
    "tokenId": "1",
    "network": "ethereum"
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for nft-metadata; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• contract and tokenId are required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/nft-metadata returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/nft-metadata", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "contract": "0xed5af388653567af2f388e6224dc7c4b3241c544",
    "tokenId": "1",
    "network": "ethereum"
  }),
});

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