---
title: "Full monthly mortgage payment (PITI): principal & interest, property tax, insurance, PMI (auto when LTV > 80%), and HOA."
method: POST
path: "/v1/lending/mortgage-payment"
tags: ["Lending"]
---

# Full monthly mortgage payment (PITI): principal & interest, property tax, insurance, PMI (auto when LTV > 80%), and HOA.

`POST /v1/lending/mortgage-payment`

## Request

- Base URL: `` (relative, and it does not resolve against the document’s source URL)
- URL: `/v1/lending/mortgage-payment`
- Auth: none declared

Full monthly mortgage payment (PITI): principal & interest, property tax, insurance, PMI (auto when LTV > 80%), and HOA.

Payment: x402 ($0.05 USDC on eip155:8453). Call unpaid to receive an HTTP 402 with requirements, then retry with the PAYMENT-SIGNATURE header. Method: loan = price − down; P&I amortized; tax = price·rate/1200; PMI applied when loan/price > 80%

## Request body

- object
  - `homePrice` number, required
  - `downPayment` number
  - `apr` number, required
  - `termMonths` number
  - `propertyTaxPct` number
  - `annualInsurance` number
  - `pmiRatePct` number
  - `monthlyHOA` number

## Response `200`

Verified result + provenance (formula, sources, reproducible SHA-256 hash).

## Other responses

- `400`: Invalid input (no charge) — body echoes the JSON Schema.
- `402`: Payment required — PAYMENT-REQUIRED header carries the x402 accepts[] quote.

---

[API](https://skmtc.dev/x402toll/apis/tollbooth-verified-calculators-for-ai-agents.md) · [All operations](https://skmtc.dev/x402toll/apis/tollbooth-verified-calculators-for-ai-agents/llms.txt) · [OpenAPI document](https://skmtc.dev/x402toll/apis/tollbooth-verified-calculators-for-ai-agents/revisions/60cb70a3e1a5?raw)