AI Inference · x402 · early usage

Mortgage schedules: level-payment/level-principal, total interest, prepayment effect (t…

Mortgage schedules: level-payment/level-principal, total interest, prepayment effect (term-reduction or payment-reduction). Deterministic annuity math. $0.005/call.

by mart402.com · discovered, not yet claimed by its owner · updated 2026-10-10

30d calls5

30d payers4

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Mortgage schedules: level-payment/level-principal, total interest, prepayment effect (term-reduction or payment-reduction). Deterministic annuity math. $0.005/call.

Tags: bazaar · offer-receipt

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-10

Input example from Bazaar metadata

{
  "annual_rate": 0.012,
  "months": 420,
  "principal_yen": 35000000
}

Output example

{
  "as_of": null,
  "assumptions": [],
  "billable": true,
  "breakdown": [],
  "carried_forward": [],
  "disclaimer": "仮定条件に基づく概算試算。税務相談・手続代行・法律相談ではない。申告・届出への使用不可。確定額は官公署または税理士・社会保険労務士等に確認のこと。",
  "not_covered": [
    "住宅ローン控除(年度別上限・省エネ区分)",
    "団信・手数料",
    "変動金利の将来予測"
  ],
  "note": "SAMPLE RESPONSE generated by the exact deterministic engine that serves production (jp-statutory has no LLM: same input always produces this byte-identical result, carrying the same rules_version and cited primary sources). Served free at /samples/{product} so you can verify the response shape, the rules_version field and the source citations before paying. No payment was taken. The sample_input shown is the catalog example input that produced this output.",
  "ok": true,
  "result": {
    "method": "level_payment",
    "monthly_payment_yen": 102095,
    "months_paid": 421,
    "schedule_head": [
      {
        "balance_yen": 34932905,
        "interest_yen": 35000,
        "month": 1,
        "payment_yen": 102095,
        "principal_yen": 67095
      },
      {
        "balance_yen": 34865742,
        "interest_yen": 34932,
        "month": 2,
        "payment_yen": 102095,
        "principal_yen": 67163
      },
      {
        "balance_yen": 34798512,
        "interest_yen": 34865,
        "month": 3,
        "payment_yen": 102095,
        "principal_yen": 67230
      }
    ],
    "schedule_tail": [
      {
        "balance_yen": 102149,
        "interest_yen": 204,
        "month": 419,
        "payment_yen": 102095,
        "principal_yen": 101891
      },
      {
        "balance_yen": 156,
        "interest_yen": 102,
        "month": 420,
        "payment_yen": 102095,
        "principal_yen": 101993
      },
      {
        "balance_yen": 0,
        "interest_yen": 0,
        "month": 421,
        "payment_yen": 156,
        "principal_yen": 156
      }
    ],
    "total_interest_yen": 7880056,
    "total_paid_yen": 42880056,
    "total_prepaid_yen": 0
  },
  "rules_version": "2026.08.18",
  "sample": true,
  "sample_input": {
    "annual_rate": 0.012,
    "months": 420,
    "principal_yen": 35000000
  },
  "sources": [
    "deterministic-annuity-math"
  ],
  "summary": "借入35,000,000円・年1.200%・420回 -> 毎月102,095円、総利息7,880,056円",
  "tool": "jp-mortgage",
  "unverified_rules": []
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/31251.json for the price and payment options.
Pay. Call GET https://mart402.com/v1/jp-mortgage. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.005 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 5 calls · 4 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.005	0xE3244a21D0d68bFa78b7CAd8C3b8777aDFbB3188	120s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xE3244a21D0d68bFa78b7CAd8C3b8777aDFbB3188",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 120
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://mart402.com/v1/jp-mortgage"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://mart402.com/v1/jp-mortgage");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://mart402.com/v1/jp-mortgage")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: mart402.com
Endpoint: https://mart402.com/v1/jp-mortgage
Machine-readable: /resources/31251.json