Convert Area

{
  "category": "area",
  "equivalents": {
    "acre": 5,
    "cm2": 202342821.1,
    "ft2": 217800,
    "ha": 2.023428211,
    "in2": 31363200,
    "km2": 0.02023428211,
    "m2": 20234.28211,
    "mi2": 0.0078125,
    "mm2": 20234282110,
    "yd2": 24200
  },
  "formula": "value x (acre per m2) / (m2 per m2)",
  "from": "acre",
  "result": 20234.282112,
  "to": "m2",
  "units": [
    "mm2",
    "cm2",
    "m2",
    "km2",
    "ha",
    "in2",
    "ft2",
    "yd2",
    "acre",
    "mi2"
  ],
  "value": 5
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://saylorinnovations.com/api/convert/area?from=acre&to=m2&value=5'

# 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 - 'https://saylorinnovations.com/api/convert/area?from=acre&to=m2&value=5' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// 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 $0.01 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.01" });
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 $0.01 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fsaylorinnovations.com%2Fapi%2Fconvert%2Farea
const res = await pay("https://saylorinnovations.com/api/convert/area?from=acre&to=m2&value=5");
console.log(res.status, await res.text());

# 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 $0.01 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.01"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://saylorinnovations.com/api/convert/area?from=acre&to=m2&value=5")
    print(res.status_code, res.text)