How much does a favicon-extract call cost?

$0.003 per call, paid in USDC on Base via x402, with no account and no API key.

What does favicon-extract return?

A JSON object with 3 top-level fields: page_url, icons and selected. The example on this page is a real call over web/fieldnotes/index.html, web/fieldnotes/icon-32.png and web/fieldnotes/icon.svg.

What happens when a favicon-extract call fails?

The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled. A 503 upstream_unavailable can follow a settled call; the x402 payments guide covers it, 429, 402 and an uncertain 500.

catalogue / tools / Images / Favicon Extract API

Favicon Extract API

Discovers a page's favicons and returns the best one decoded to a normalised PNG with its size.

Endpoint: POST /v1/favicon-extract
Price: $0.003 per call
Family: Images
Docs: /docs/favicon-extract

01When to use it

It fans out over URLs a page author wrote and must decode several icon formats: an agent that does this itself walks past every SSRF control and becomes a request amplifier, and hand-rolling ICO/SVG decoding is not inline work.

When not to use it

The input is over 25 MB (26,214,400 bytes): favicon-extract answers too_large (413).
The destination needs more than 45 s to answer: the call ends with upstream_timeout (424).
The destination is on a private or local network: the network guard refuses it with blocked_target (403).

02Parameters

Field	Type	Required	Description
url	string	yes	Absolute http(s) URL of the web page whose icon <link> tags (rel icon, shortcut, apple-touch-icon or mask-icon) are read, up to 2048 characters; /favicon.ico on its origin is added as a last candidate and icons are only fetched from the same registrable domain.

03Limits

Limit	Value
Size cap	25 MB (26,214,400 bytes)
Timeout	45 s

04Example

The published example of favicon-extract, verbatim: the request body and the response it returns.

Request

POST /v1/favicon-extract
content-type: application/json
payment-signature: <base64 x402 payload>

{
  "url": "https://grist.tools/samples/web/fieldnotes/index.html"
}

Response

200 OK
payment-response: <base64 settlement receipt>

{
  "page_url": "https://grist.tools/samples/web/fieldnotes/index.html",
  "icons": [
    {
      "url": "https://grist.tools/samples/web/fieldnotes/icon-32.png",
      "rel": "icon",
      "type": "image/png",
      "sizes": "32x32"
    },
    {
      "url": "https://grist.tools/samples/web/fieldnotes/icon.svg",
      "rel": "icon",
      "type": "image/svg+xml",
      "sizes": null
    },
    {
      "url": "https://grist.tools/favicon.ico",
      "rel": "icon",
      "type": null,
      "sizes": null
    }
  ],
  "selected": {
    "url": "https://grist.tools/samples/web/fieldnotes/icon-32.png",
    "source_format": "png",
    "width": 32,
    "height": 32,
    "bytes": 106,
    "image_base64": "iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAACXBIWXMAAAsSAAALEgHS3X78AAAAMUlEQVRIx2PQjw2gKWIYtWDUgiFswaf3z0hCoxaMWjBqwagFoxYMTwtGq8xRC0aQBQBMN1tMlMrjbQAAAABJRU5ErkJggg=="
  }
}

Sample file: web/fieldnotes/index.html. Sample file: web/fieldnotes/icon-32.png. 32x32 RGB PNG favicon of the Field Notes sample site, built byte by byte with node:zlib. Sample file: web/fieldnotes/icon.svg. SVG favicon of the Field Notes sample site, the same drawing as icon-32.png.

Response field	Type	In the example
page_url	string	"https://grist.tools/samples/web/fieldnotes/index.html"
icons	array	3 items, each with url, rel, type and sizes
selected	object	an object with url, source_format, width, height, bytes and image_base64

05Call it from code

JavaScript

// favicon-extract: $0.003 per call, paid in USD Coin on eip155:8453 via x402
// Install: npm install @x402/fetch@2 @x402/evm@2 viem@2
// Save as client.mjs (ES module, Node 18+), export EVM_PRIVATE_KEY with the paying wallet's key in your shell, then run: node client.mjs
// The wrapper reads the 402 (payment-required), signs and retries with payment-signature.
import { wrapFetchWithPayment, x402Client, decodePaymentResponseHeader } from '@x402/fetch'
import { ExactEvmScheme } from '@x402/evm/exact/client'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY)
const client = new x402Client().register('eip155:8453', new ExactEvmScheme(account))
const fetchWithPayment = wrapFetchWithPayment(fetch, client)

const body = {
  "url": "https://grist.tools/samples/web/fieldnotes/index.html"
}

const res = await fetchWithPayment('https://grist.tools/v1/favicon-extract', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify(body),
})
console.log(res.status, await res.json())
const settle = res.headers.get('payment-response')
if (settle) console.log(decodePaymentResponseHeader(settle).transaction)

Python

# favicon-extract: $0.003 per call, paid in USD Coin on eip155:8453 via x402
# Install: pip install "x402[requests,evm]>=2.24,<3"
# The session reads the 402 (payment-required), signs and retries with payment-signature.
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http import decode_payment_response_header
from x402.http.clients.requests import x402_requests
from x402.mechanisms.evm.exact import register_exact_evm_client
from x402.mechanisms.evm.signers import EthAccountSigner

account = Account.from_key(os.environ["EVM_PRIVATE_KEY"])
client = x402ClientSync()
register_exact_evm_client(client, EthAccountSigner(account), networks="eip155:8453")
session = x402_requests(client)

payload = {
    "url": "https://grist.tools/samples/web/fieldnotes/index.html"
}

res = session.post("https://grist.tools/v1/favicon-extract", json=payload)
print(res.status_code, res.json())
settle = res.headers.get("payment-response")
if settle:
    print(decode_payment_response_header(settle).transaction)

curl

# favicon-extract: $0.003 per call, paid in USD Coin on eip155:8453 via x402
# 1. Unpaid call: HTTP 402, the requirements in the payment-required header (base64 JSON) and in the body.
curl -i -X POST 'https://grist.tools/v1/favicon-extract' -H 'content-type: application/json' -d '{"url":"https://grist.tools/samples/web/fieldnotes/index.html"}'

# 2. Same call with the signed payment (an EIP-3009 authorization, EIP-712 signed: it cannot be
#    typed by hand). x-payment is accepted as the v1 alternative. HTTP 200 carries payment-response.
curl -i -X POST 'https://grist.tools/v1/favicon-extract' -H 'content-type: application/json' -H 'payment-signature: <base64 x402 payload>' -d '{"url":"https://grist.tools/samples/web/fieldnotes/index.html"}'

06Errors

Code	HTTP	For this service
invalid_input	400	The body does not match the schema; its fields are url.
blocked_target	403
unreachable_target	424
upstream_timeout	424
unsupported_content_type	415
too_large	413
unprocessable	422
internal	500

Input that is rejected before the tool runs (malformed JSON, schema mismatch, body over the size limit) is never charged.

When each code is raised, and what it means for payment: /docs/favicon-extract.

07Questions

How much does a favicon-extract call cost?: $0.003 per call, paid in USDC on Base via x402, with no account and no API key.
What does favicon-extract return?: A JSON object with 3 top-level fields: page_url, icons and selected. The example on this page is a real call over web/fieldnotes/index.html, web/fieldnotes/icon-32.png and web/fieldnotes/icon.svg.
What happens when a favicon-extract call fails?: The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled. A 503 upstream_unavailable can follow a settled call; the x402 payments guide covers it, 429, 402 and an uncertain 500.