Loan amortization schedule API on Base, paid per-call via x402 in USDC.
What it does
This endpoint at lowpaymentfee.com returns a loan amortization schedule for a given loan (identified by ID in the URL path). It is part of a broader platform offering dozens of pay-per-request 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 specific endpoint `/api/v1/loans/42/schedule` accepts POST requests and returns JSON. Payment is handled inline: callers attach an X-PAYMENT header with a valid x402 payment proof. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 USD — consistent with the site's advertised flat $0.02/request pricing across all endpoints. No API keys, rate limits, or upfront commitments are required.
The platform advertises itself as a low-friction, keyless API marketplace. Documentation pages exist at /docs, /api, /pricing, and /README but currently render only a "Connect wallet" prompt with no substantive content, so detailed request/response schemas are unavailable. The loan schedule endpoint's exact input parameters (e.g., principal, rate, term) and output fields are not documented in the crawled material, so callers will need to experiment or wait for fuller docs.
Capabilities
Use cases
- —Generate an amortization schedule for a specific loan to see payment breakdowns over time
- —Integrate loan schedule data into a fintech dashboard or lending application
- —Allow AI agents to autonomously fetch loan repayment details with instant crypto micropayments
Fit
Best for
- —Developers needing on-demand loan amortization data without API key management
- —AI agents that can settle payments autonomously via x402 on Base
- —Fintech prototypes requiring quick, low-cost access to financial calculation endpoints
Not for
- —Production systems that need detailed, documented request/response schemas (docs are currently empty)
- —Users who cannot pay with USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/loans/42/schedule \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it exists and accepts payments. However, all documentation pages render only 'Connect wallet' with no content. There is no OpenAPI spec, no request/response schema, and no examples — making the endpoint essentially a stub from a documentation perspective. The loan-specific path (/loans/42/schedule) suggests a fixed demo resource rather than a parameterized API.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no usable content.
- —No request body schema or response schema is documented; input parameters for the loan schedule are unknown.
- —The endpoint path includes a hardcoded loan ID (42), which may be a demo resource rather than a general-purpose API.
- —The endpoint is not listed on the provider's own homepage among their advertised APIs, raising questions about its status.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/loans/42/schedule
- —The platform advertises $0.02/request flat 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/42/schedule
- —Documentation pages render only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs