Loan amortization schedule API, pay-per-call at $0.02 via USDC on Base.
What it does
This endpoint at lowpaymentfee.com generates a loan amortization schedule for a 30-year term (based on the URL path `/api/v1/loans/30/schedule`). It is part of a broader platform offering pay-per-request APIs across data analytics, AI/ML, finance, and utility categories, all settled via the x402 protocol using USDC on the Base network.
The endpoint accepts POST requests and returns JSON. Payment is handled inline via the x402 protocol: callers include an `X-PAYMENT` header with a signed payment of up to $0.02 (20,000 base units of USDC, which has 6 decimals) per request. There are no API keys, no rate limits, and no subscription commitments — each call is independently paid. The payment is sent to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on Base mainnet, settling against the USDC contract at `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`.
Documentation on the site is extremely sparse — the docs, pricing, and API pages all render only a "Connect wallet" prompt with no further content. The specific request body schema for this loans endpoint (e.g., what parameters like principal, interest rate, or start date it expects) is not documented anywhere in the crawled material. The 30 in the URL path likely refers to a 30-year loan term, but this is inferred from convention, not confirmed by documentation.
Capabilities
Use cases
- —Generating a 30-year loan amortization schedule for mortgage or lending applications
- —Integrating loan payment breakdowns into fintech dashboards
- —Agent-driven financial planning that needs per-call amortization data
- —Comparing loan structures programmatically without API key management
Fit
Best for
- —Developers needing on-demand loan amortization without subscriptions
- —AI agents that can settle USDC payments on Base via x402
- —Fintech prototypes requiring quick, keyless access to financial calculations
Not for
- —Users who need detailed API documentation before integrating
- —Applications requiring non-crypto payment methods
- —High-volume batch processing where per-call pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/loans/30/schedule \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-signed-payment>" \
-d '{"principal": 300000, "annualRate": 0.065}'Example
Request
{
"principal": 300000,
"annualRate": 0.065
}Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on request/response schemas. The docs, pricing, and API pages are all empty beyond a wallet-connect prompt. The request body and response format are entirely unknown, making this effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, and API pages all render only 'Connect wallet' with no content.
- —Request body schema for the loans endpoint is completely undocumented; the example request is speculative.
- —Response format is unknown — no example or schema provided by the source.
- —The '30' in the URL path is assumed to mean 30-year term but is not confirmed anywhere.
- —This specific endpoint (/api/v1/loans/30/schedule) is not listed on the provider's homepage among their advertised APIs.
Citations
- —The endpoint returns a 402 challenge requiring USDC payment on Base network with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/v1/loans/30/schedule
- —USDC contract address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/loans/30/schedule
- —Platform pricing is $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform advertises APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com