Finance Amortization Schedule

{
  "result": {
    "answer": "1,520.06/mo · paid off in 360 months (30.0 yrs)",
    "answerLabel": "300,000 @ 4.5% / 30y",
    "details": [
      {
        "label": "Monthly payment (P&I)",
        "value": "1,520.06"
      },
      {
        "label": "Total interest",
        "value": "247,220.13"
      },
      {
        "label": "Total paid",
        "value": "547,220.13"
      }
    ],
    "steps": [
      "Payment = P·i/(1−(1+i)^−n) with i = 0.003750, n = 360 → 1,520.06",
      "Simulated 360 months"
    ],
    "table": {
      "columns": [
        "Year",
        "Principal paid",
        "Interest paid",
        "Balance"
      ],
      "rows": [
        [
          1,
          "4,839.68",
          "13,400.99",
          "295,160.32"
        ],
        [
          2,
          "5,062.01",
          "13,178.66",
          "290,098.31"
        ],
        [
          3,
          "5,294.56",
          "12,946.11",
          "284,803.74"
        ],
        [
          4,
          "5,537.79",
          "12,702.88",
          "279,265.95"
        ],
        [
          5,
          "5,792.2",
          "12,448.47",
          "273,473.75"
        ],
        [
          6,
          "6,058.29",
          "12,182.38",
          "267,415.46"
        ],
        [
          7,
          "6,336.61",
          "11,904.06",
          "261,078.85"
        ],
        [
          8,
          "6,627.71",
          "11,612.96",
          "254,451.14"
        ],
        [
          9,
          "6,932.19",
          "11,308.48",
          "247,518.95"
        ],
        [
          10,
          "7,250.65",
          "10,990.02",
          "240,268.3"
        ],
        [
          11,
          "7,583.74",
          "10,656.93",
          "232,684.56"
        ],
        [
          12,
          "7,932.14",
          "10,308.53",
          "224,752.42"
        ],
        [
          13,
          "8,296.54",
          "9,944.13",
          "216,455.88"
        ],
        [
          14,
          "8,677.68",
          "9,562.99",
          "207,778.2"
        ],
        [
          15,
          "9,076.33",
          "9,164.34",
          "198,701.86"
        ],
        [
          16,
          "9,493.3",
          "8,747.37",
          "189,208.57"
        ],
        [
          17,
          "9,929.42",
          "8,311.25",
          "179,279.15"
        ],
        [
          18,
          "10,385.57",
          "7,855.1",
          "168,893.57"
        ],
        [
          19,
          "10,862.69",
          "7,377.98",
          "158,030.89"
        ],
        [
          20,
          "11,361.72",
          "6,878.95",
          "146,669.17"
        ]
      ]
    },
    "value": 1520.055929
  },
  "tool": "amortization-schedule"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://agentstoolshub.com/api/v1/finance/amortization-schedule?annualRate=4.5&principal=300000&years=30'

# 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://agentstoolshub.com/api/v1/finance/amortization-schedule?annualRate=4.5&principal=300000&years=30' \
  | 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 $0.003 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.003" });
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 $0.003 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fagentstoolshub.com%2Fapi%2Fv1%2Ffinance%2Famortization-schedule
const res = await pay("https://agentstoolshub.com/api/v1/finance/amortization-schedule?annualRate=4.5&principal=300000&years=30");
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 $0.003 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.003"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://agentstoolshub.com/api/v1/finance/amortization-schedule?annualRate=4.5&principal=300000&years=30")
    print(res.status_code, res.text)