---
title: "Auto-loan payment including state sales tax (verified 2026 rates), trade-in credit, down payment, and fees."
method: POST
path: "/v1/lending/auto-loan"
tags: ["Lending"]
---

# Auto-loan payment including state sales tax (verified 2026 rates), trade-in credit, down payment, and fees.

`POST /v1/lending/auto-loan`

## Request

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

Auto-loan payment including state sales tax (verified 2026 rates), trade-in credit, down payment, and fees.

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: tax = (price − tradeIn)·stateRate; financed = price − down − tradeIn + tax + fees; payment amortized

## Request body

- object
  - `vehiclePrice` number, required
  - `downPayment` number
  - `tradeInValue` number
  - `state` string
  - `salesTaxLocalPct` number
  - `fees` number
  - `apr` number, required
  - `termMonths` 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)