Pace Race

{
  "asOf": "2026-10-11T08:36:51.391Z",
  "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.",
  "distanceKm": 5,
  "distanceMiles": 3.106856,
  "formula": "Riegel exponent 1.06",
  "notChecked": [
    "course, weather and training: Riegel assumes you are trained for the longer distance and over-predicts fast marathon times for low-mileage runners",
    "predictions below about 1 mile or above the marathon",
    "…1 more"
  ],
  "pacePerKm": "5:00",
  "pacePerMile": "8:03",
  "predictions": {
    "10k": "52:07",
    "1500m": "6:59",
    "3k": "14:33",
    "half": "1:55:00",
    "marathon": "3:59:47",
    "mile": "7:31"
  },
  "reasons": [
    "Riegel: T2 = T1 x (D2 / D1)^1.06. It is a rule of thumb: marathon predictions from a 5k are optimistic without marathon training."
  ],
  "source": "computed locally",
  "speedKmh": 12,
  "speedMph": 7.45645,
  "summary": "5 km in 25:00: 5:00 per km, 8:03 per mile, 12 km/h. Predicted: 1500m 6:59, mile 7:31, 3k 14:33, 10k 52:07, half 1:55:00.",
  "time": "25:00",
  "timeSeconds": 1500,
  "verdict": "COMPUTED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://fitness-calc.x402tookit.com/pace-race?distance=5k&time=25%3A00'

# 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/pace-race?distance=5k&time=25%3A00' \
  | 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%2Fpace-race
const res = await pay("https://fitness-calc.x402tookit.com/pace-race?distance=5k&time=25%3A00");
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/pace-race?distance=5k&time=25%3A00")
    print(res.status_code, res.text)