ENS resolve

Resolve an ENS name (e.g. vitalik.eth) to its Ethereum address - so an agent can turn a human-readable recipient into a payable address. Send GET /api/ens-resolve with the required field name and pay $0.001 per call over x402 or MPP (there is no free tier). It returns a JSON object with name, address and found.

Read-only on Ethereum mainnet. ?name=vitalik.eth

Category: Payments & x402 · Tags: ens resolve ethereum name address lookup · Also found as: ens

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Parameters

Example request

curl -i "https://agent402.tools/api/ens-resolve?name=vitalik.eth"

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

Example response

{
  "name": "vitalik.eth",
  "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "found": true
}

From an MCP client

catalog.call {
  "slug": "ens-resolve",
  "params": {
    "name": "vitalik.eth"
  }
}

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

Errors and behavior

• name is 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.
• Cached: an identical request within 1h is answered from cache with X-Cache: hit.
• A POST with a JSON body to /api/ens-resolve is served as this GET, with the body as the input.
• 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/ens-resolve?name=vitalik.eth");

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