Towing Payload

{
  "asOf": "2026-10-11T14:38:38.697Z",
  "combinedWeightLb": 11500,
  "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.",
  "gcwrLb": 13500,
  "gcwrRemainingLb": 2000,
  "issues": [],
  "notChecked": [
    "axle ratings, tire load ratings, hitch class and receiver ratings, which can each be lower than the numbers here",
    "braking, trailer brake controllers, stability and local laws",
    "…2 more"
  ],
  "occupantsAndCargoLb": 600,
  "payloadCapacityLb": 1900,
  "payloadRemainingLb": 580,
  "payloadUsedLb": 1320,
  "reasons": [
    "Payload = GVWR - curb weight; tongue weight counts against payload.",
    "Combined weight = curb + people and cargo + trailer, compared with GCWR."
  ],
  "source": "computed locally",
  "summary": "Within the ratings you entered: payload 1900 lb, tongue weight 720 lb, 580 lb of payload left; trailer 6000 of 7500 lb rated.",
  "tongueWeightLb": 720,
  "towRatingLb": 7500,
  "towRatingRemainingLb": 1500,
  "trailerAsPercentOfTowRating": 80,
  "trailerWeightLb": 6000,
  "verdict": "WITHIN_ENTERED_RATINGS"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://automotive-calc.x402tookit.com/towing-payload?curbWeight=4900&gcwr=13500&gvwr=6800&occupantsAndCargo=600&tonguePercent=12&towRating=7500&trailerWeight=6000'

# 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://automotive-calc.x402tookit.com/towing-payload?curbWeight=4900&gcwr=13500&gvwr=6800&occupantsAndCargo=600&tonguePercent=12&towRating=7500&trailerWeight=6000' \
  | 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%2Fautomotive-calc.x402tookit.com%2Ftowing-payload
const res = await pay("https://automotive-calc.x402tookit.com/towing-payload?curbWeight=4900&gcwr=13500&gvwr=6800&occupantsAndCargo=600&tonguePercent=12&towRating=7500&trailerWeight=6000");
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://automotive-calc.x402tookit.com/towing-payload?curbWeight=4900&gcwr=13500&gvwr=6800&occupantsAndCargo=600&tonguePercent=12&towRating=7500&trailerWeight=6000")
    print(res.status_code, res.text)