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 28 in the URL path). 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 via the x402 protocol on the Base network using USDC.
The endpoint is live and returns a 402 challenge requesting payment of up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) per request. Payment is made via an exact-scheme x402 header to the specified wallet address. The response MIME type is application/json. The endpoint accepts POST requests and is marked as discoverable.
Documentation beyond the landing page is extremely thin — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what fields the loan schedule response contains or what POST body (if any) is expected. The specific loan ID 28 is hardcoded in the path, and it is unclear whether other loan IDs are available or how loans are created. Users should expect to experiment with the endpoint to discover its behavior.
Capabilities
Use cases
- —Retrieving a loan amortization schedule showing principal and interest breakdowns per 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 on-demand loan schedule data without API key management
- —AI agents that can settle x402 micropayments for financial data
- —Applications requiring pay-per-use loan amortization calculations
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —Bulk loan schedule generation (no evidence of batch support or parameterized loan creation)
- —Non-crypto payment workflows — only USDC on Base is accepted
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/loans/28/schedule \
-H "X-PAYMENT: <x402-payment-header>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation of what the loan schedule contains, and no examples. The loan ID is hardcoded in the path with no explanation. Docs pages are empty beyond a wallet connect prompt. This is effectively a stub listing.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content
- —No request body schema documented; unclear what POST body (if any) is expected
- —Loan ID 28 is hardcoded in the endpoint path; no documentation on how loans are created or whether other IDs exist
- —No response schema or example response available
- —No OpenAPI or ai-plugin manifest found
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/loans/28/schedule
- —The platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/loans/28/schedule