Site favicon grabber

Fetch a site's favicon/logo: reads the page's declared <link rel=icon…> tags (all variants with their sizes and types), deterministically picks the largest declared icon (falling back to /favicon.ico), fetches it, and returns the bytes as a base64 data URI plus the resolved icon URL and content type. Send POST /api/favicon-grab with the required field url and pay $0.003 per call over x402 or MPP (there is no free tier). It returns a JSON object with found, url, iconUrl, finalIconUrl, contentType and 3 more.

Icons over 256KB return the URL and metadata without the inline data URI. SSRF-guarded - private-network hosts are rejected. Sites with no reachable icon return {found:false}.

Category: Web & documents · Tags: web favicon icon logo enrichment domain brand · Also found as: site-favicon-grabber favicon

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/favicon-grab \
  -H "Content-Type: application/json" \
  -d '{"url":"https://agent402.tools"}'

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

Example response

{
  "found": true,
  "url": "https://agent402.tools/",
  "iconUrl": "https://agent402.tools/favicon.ico?v=3",
  "finalIconUrl": "https://agent402.tools/favicon.ico?v=3",
  "contentType": "image/png",
  "bytes": 76462,
  "dataUri": "data:image/png;base64,iVBORw0KGgo…",
  "declared": [
    {
      "href": "https://agent402.tools/favicon.svg?v=3",
      "rel": "icon",
      "sizes": null,
      "type": "image/svg+xml",
      "mask": false
    },
    {
      "href": "https://agent402.tools/favicon.ico?v=3",
      "rel": "icon",
      "sizes": "512x512",
      "type": "image/png",
      "mask": false
    },
    {
      "href": "https://agent402.tools/favicon.ico?v=3",
      "rel": "shortcut icon",
      "sizes": null,
      "type": null,
      "mask": false
    },
    {
      "href": "https://agent402.tools/logo.png?v=2",
      "rel": "apple-touch-icon",
      "sizes": null,
      "type": null,
      "mask": false
    }
  ]
}

From an MCP client

catalog.call {
  "slug": "favicon-grab",
  "params": {
    "url": "https://agent402.tools"
  }
}

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

Errors and behavior

• url 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/favicon-grab 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/favicon-grab", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "url": "https://agent402.tools"
  }),
});

Part of these workflows

Site favicon grabber is one step in this skill pack, each sold as a single call:

• Entity enrichment - Company name → verified identity + web footprint dossier: Wikidata facts, the official LEI legal-entity record, the SEC EDGAR filer, domain registration, tech stack, and brand favicon - in one pass.

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