Calorie Burn

{
  "activity": "running-6mph",
  "asOf": "2026-10-11T08:36:49.821Z",
  "availableActivities": [
    "walking-3mph",
    "walking-3.5mph",
    "…21 more"
  ],
  "compendium": "2011 Compendium of Physical Activities",
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "grossKcal": 360,
  "grossKcalPerHour": 720,
  "met": 9.8,
  "minutes": 30,
  "netKcal": 323,
  "notChecked": [
    "your actual fitness, efficiency, terrain, wind and intensity (MET values are averages: real burn varies by 20% or more)",
    "calories you would have burned anyway at rest (the figure is gross; net exercise calories are about 1 MET less, so subtract kg x minutes / 60)",
    "…2 more"
  ],
  "reasons": [
    "kcal per minute = MET x 3.5 x kg / 200 (the standard ACSM conversion; MET x kg x hours gives nearly the same).",
    "MET values are Compendium averages, so treat the result as a ballpark."
  ],
  "source": "computed locally",
  "summary": "running-6mph for 30 min at 70 kg: about 360 kcal gross (323 kcal above resting), MET 9.8.",
  "verdict": "ESTIMATED",
  "weightKg": 70
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://fitness-calc.x402tookit.com/calorie-burn?activity=running-6mph&minutes=30&weight=70'

# 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://fitness-calc.x402tookit.com/calorie-burn?activity=running-6mph&minutes=30&weight=70' \
  | 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 $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
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 $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Ffitness-calc.x402tookit.com%2Fcalorie-burn
const res = await pay("https://fitness-calc.x402tookit.com/calorie-burn?activity=running-6mph&minutes=30&weight=70");
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 $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://fitness-calc.x402tookit.com/calorie-burn?activity=running-6mph&minutes=30&weight=70")
    print(res.status_code, res.text)