Farcaster user search

Search Farcaster users by name or username fragment. Send POST /api/fc-user-search with the required field q and pay $0.003 per call over x402 or MPP (there is no free tier). It returns a JSON object with source, fetchedAt, cached, rateLimit, query and 3 more.

Returns up to 10 compact profiles: fid, username, display name, bio, follower and following counts, Neynar quality score, primary verified Ethereum address. Use to resolve a person or brand to a fid before fc-user-casts, or to find who to follow on a topic.

Category: Web & documents · Tags: farcaster social user search profile

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/fc-user-search \
  -H "Content-Type: application/json" \
  -d '{"q":"example","limit":3}'

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

Example response

{
  "source": "neynar",
  "fetchedAt": "2026-08-22T13:19:12.000Z",
  "cached": false,
  "rateLimit": {
    "limit": 300,
    "remaining": 299,
    "resetAt": "2026-08-22T13:20:00.000Z"
  },
  "query": "example",
  "count": 1,
  "users": [
    {
      "fid": 3,
      "username": "example-user",
      "displayName": "Example User",
      "bio": "Example profile used only to show the response shape.",
      "pfpUrl": "https://imagedelivery.net/.../original",
      "followerCount": 630338,
      "followingCount": 77,
      "powerBadge": false,
      "score": 0.99,
      "primaryEthAddress": "0x6ce09ed5526de4afe4a981ad86d17b2f5c92fea5",
      "url": "https://warpcast.com/dwr"
    }
  ],
  "nextCursor": null
}

From an MCP client

catalog.call {
  "slug": "fc-user-search",
  "params": {
    "q": "example",
    "limit": 3
  }
}

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

Errors and behavior

• q 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.
• A GET or HEAD to /api/fc-user-search 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/fc-user-search", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "q": "example",
    "limit": 3
  }),
});

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