ToolVet
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Farcaster By Address

by Farcaster by Ethereum address in Onchain & crypto

x402 APIPassing, checked 4 h ago

Reverse-lookup an Ethereum address to its Farcaster account (via verified address). Returns FID, username, display name, bio, follower/following counts, and Warpcast URL, or found=false if the address has not verified on Farcaster. Use to label wallet activity with the owner's Farcaster identity when ENS is missing.

POST
https://agent402.tools/api/farcaster-by-address
Price
$0.002
per call in USDC
Uptime
100%
last 30 days
Response time
278 ms
459 ms slowest 5%
Last check
Passed
4 h ago, next any minute now

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed

How to call it

POST https://agent402.tools/api/farcaster-by-address

Each call costs $0.002 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://agent402.tools/api/farcaster-by-address
content-type: application/json

{
  "address": "0xd7029bdea1c17493893aafe29aad69ef892b8ff2"
}

Parameters

ParameterTypeRequiredDescription
addressstringYesEthereum address (0x-prefixed 40-hex).

Example response

The provider's example. We can't check it without paying.

{
  "address": "0xd7029bdea1c17493893aafe29aad69ef892b8ff2",
  "bio": "Working on Farcaster.",
  "displayName": "Dan Romero",
  "fid": 3,
  "followerCount": 500000,
  "followingCount": 1000,
  "found": true,
  "pfpUrl": "https://...",
  "source": "neynar",
  "username": "dwr",
  "venueUrl": "https://warpcast.com/dwr"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.002.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://agent402.tools/api/farcaster-by-address' \
  -H 'content-type: application/json' \
  --data-raw '{"address":"0xd7029bdea1c17493893aafe29aad69ef892b8ff2"}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://agent402.tools/api/farcaster-by-address' \
  -H 'content-type: application/json' \
  --data-raw '{"address":"0xd7029bdea1c17493893aafe29aad69ef892b8ff2"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.002 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.002" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.002 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fagent402.tools%2Fapi%2Ffarcaster-by-address&method=POST
const res = await pay("https://agent402.tools/api/farcaster-by-address", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "address": "0xd7029bdea1c17493893aafe29aad69ef892b8ff2"
  }),
});
console.log(res.status, await res.text());
Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.002 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.002"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://agent402.tools/api/farcaster-by-address",
        json={
            "address": "0xd7029bdea1c17493893aafe29aad69ef892b8ff2",
        },
    )
    print(res.status_code, res.text)

Security scan

No findings

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Recent checks

WhenResultHTTPTimePrice
4 h agoPassed402278 ms$0.002
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12 h agoPassed402189 ms$0.002
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25 h agoPassed402201 ms$0.002
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