Loan amortization schedule API, pay-per-request via x402 on Base (USDC).
What it does
This endpoint at lowpaymentfee.com returns a loan amortization schedule for a specific loan (loan ID 18) via a POST request. It is part of a broader platform offering various pay-per-call APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services — all settled through the x402 payment protocol on the Base network using USDC.
The x402 challenge confirms the endpoint is live and accepts payments of up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this translates to a maximum cost of $0.02 per request. The platform advertises uniform $0.02/request pricing across all endpoints, with no API keys, no rate limits, and no minimum commitments required.
Note that the specific endpoint path references loan ID 18, suggesting it may serve a fixed or demo loan schedule rather than being a general-purpose loan calculator. No OpenAPI schema, request body documentation, or response examples were found in the crawl — the docs, pricing, and API pages all returned only a "Connect wallet" prompt with no substantive content. As a result, the exact request format and response structure are unknown and must be discovered by the caller.
Capabilities
Use cases
- —Retrieving an amortization schedule showing principal and interest breakdowns per payment period
- —Integrating loan schedule data into financial planning tools or dashboards
- —Agent-driven financial calculations that need structured loan repayment data
Fit
Best for
- —Developers needing quick, keyless access to loan schedule data
- —AI agents that can pay per-call via x402 on Base
- —Prototyping financial applications without signup or API key management
Not for
- —Production loan origination systems requiring configurable loan parameters (loan ID is hardcoded to 18)
- —Users who need detailed API documentation or guaranteed SLAs
- —Applications requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/loans/18/schedule \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response documentation, no examples, and the docs pages are empty. The hardcoded loan ID 18 in the path raises questions about the endpoint's general utility.
Warnings
- —No API documentation found — docs, pricing, and API pages return only a wallet-connect prompt with no content.
- —Endpoint path hardcodes loan ID 18; unclear if other loan IDs are supported or how to parameterize.
- —No request body schema or response schema available; callers must discover the interface by trial.
- —The broader platform lists many endpoint categories but none were verified beyond this single endpoint.
Citations
- —The endpoint returns HTTP 402 with an x402 challenge requiring up to 20,000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/loans/18/schedule
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/loans/18/schedule
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com