URL to Markdown API

POST /v1/url-to-markdown
content-type: application/json
payment-signature: <base64 x402 payload>

{
  "url": "https://kitchen-ledger.blog/posts/weekday-starter",
  "max_chars": 2000
}

// url-to-markdown: $0.002 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://kitchen-ledger.blog/posts/weekday-starter",
  "max_chars": 2000
}

const res = await fetchWithPayment('https://grist.tools/v1/url-to-markdown', {
  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)

# url-to-markdown: $0.002 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://kitchen-ledger.blog/posts/weekday-starter",
    "max_chars": 2000
}

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

# url-to-markdown: $0.002 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/url-to-markdown' -H 'content-type: application/json' -d '{"url":"https://kitchen-ledger.blog/posts/weekday-starter","max_chars":2000}'

# 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/url-to-markdown' -H 'content-type: application/json' -H 'payment-signature: <base64 x402 payload>' -d '{"url":"https://kitchen-ledger.blog/posts/weekday-starter","max_chars":2000}'

200 OK
payment-response: <base64 settlement receipt>

{
  "title": "Feeding a Sourdough Starter on a Weekday Schedule",
  "byline": "Marta Rinaldi",
  "excerpt": "A feeding routine that keeps a rye starter active on a nine-to-five schedule, with ratios and timings.",
  "site_name": "Kitchen Ledger",
  "lang": "en",
  "markdown": "By [Marta Rinaldi](https://kitchen-ledger.blog/authors/marta-rinaldi/)\n\nMost starter guides assume you are home all day, ready to feed every twelve hours on the dot. A starter kept on a weekday routine can stay just as lively, provided the flour, the ratio and the temperature do the work that a flexible timetable cannot.\n\n## The ratio that buys you time\n\nA stiffer, less frequently fed starter ferments more slowly. Feeding one part starter to five parts flour and five parts water stretches the peak from four hours to roughly ten at a kitchen temperature of twenty-two degrees, which is long enough to cover a working day.\n\n-   Morning, before work: discard all but 10 g and feed 50 g flour and 50 g water.\n-   Evening: use the starter at its peak, or refrigerate it overnight.\n-   Weekend: return to two feeds a day at one to one to one if you plan to bake.\n\n## Choosing the flour\n\nWhole rye ferments faster and more predictably than white wheat, so a small share of it keeps a slow schedule from stalling. The [guide to flour protein](https://kitchen-ledger.blog/guides/flour-protein/) explains why, and the [baker's percentage tables](https://www.bakerspercentage.net/tables) help when you scale a recipe up.\n\nIf the starter smells sharply of acetone by evening, it is hungry: shorten the interval or lower the temperature rather than adding more flour at once.",
  "length": 1368,
  "truncated": false,
  "readability_applied": true,
  "url_final": "https://kitchen-ledger.blog/posts/weekday-starter",
  "fetched_at": "2026-09-26T09:30:00.000Z"
}

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "url": {
      "type": "string",
      "maxLength": 2048,
      "format": "uri",
      "description": "Page to fetch, http or https. Redirects are followed and every hop is checked against private and reserved addresses."
    },
    "max_chars": {
      "default": 50000,
      "description": "Cut applied to the returned markdown, counted in Unicode code points.",
      "type": "integer",
      "minimum": 200,
      "maximum": 200000
    }
  },
  "required": [
    "url"
  ],
  "additionalProperties": false
}