Loan amortization schedule API, pay-per-request via x402 on Base (USDC).
What it does
This endpoint at lowpaymentfee.com provides a loan amortization schedule for a specific loan (loan ID 57) via a POST request. It is part of a broader platform offering various pay-per-call APIs across data analytics, AI/ML, finance, and utility categories, all settled through the x402 payment protocol on the Base network using USDC.
The endpoint returns JSON (application/json) and costs $0.02 per request (20,000 base units of USDC with 6 decimals). Payment is handled inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required. The x402 challenge was successfully captured, confirming the endpoint is live and accepting payments to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second payment timeout.
Documentation is extremely sparse. The crawled docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no description of request parameters, and no example responses. The endpoint path suggests it returns a payment schedule for loan 57, but the exact input format and output structure are unknown. The broader site advertises a uniform $0.02/request pricing model across all endpoints.
Capabilities
Use cases
- —Retrieving a loan amortization schedule showing principal and interest breakdowns per period
- —Integrating loan payment schedule data into financial planning tools
- —Agent-driven financial calculations that need on-demand loan schedule generation
Fit
Best for
- —Developers needing a simple pay-per-call loan schedule endpoint without API key management
- —AI agents that can settle USDC payments on Base for financial data
- —Quick one-off loan schedule lookups without subscription commitments
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume batch loan calculations where per-request pricing adds up
- —Users without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/loans/57/schedule \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/request in USDC on Base), but there is no documentation, no request/response schema, no examples, and the endpoint is scoped to a single hardcoded loan ID (57) with no explanation of what parameters it accepts or what the response looks like.
Warnings
- —No API documentation available — docs, pricing, and README pages all return only a wallet-connect prompt
- —No OpenAPI or request/response schema provided; input format and output structure are entirely unknown
- —Endpoint path is hardcoded to loan ID 57; unclear if this is parameterizable or a demo fixture
- —The broader site lists many endpoint categories but this specific loans endpoint is not listed on the homepage
Citations
- —Endpoint returns 402 with x402 challenge advertising USDC payment on Base network at 20000 base unitshttps://lowpaymentfee.com/api/v1/loans/57/schedule
- —Site advertises $0.02/request uniform pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/loans/57/schedule