Loan amortization schedule API, pay-per-call at $0.02 via USDC on Base.
What it does
This endpoint at lowpaymentfee.com provides a loan amortization schedule via a POST request to `/api/v1/loans/99/schedule`. 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 gated by the x402 payment protocol on the Base network.
The endpoint is live and returns a standard x402 402 challenge. Payment is settled in USDC (contract `0x8335…2913` on Base) using the "exact" scheme. The maximum amount required is 20,000 base units, which at 6 decimals for USDC equals $0.02 per request. No API keys or rate limits are advertised; access is granted instantly upon payment. The payment timeout is 300 seconds.
Documentation is extremely thin — the docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no additional technical content. There is no OpenAPI spec, no request/response schema, and no example payloads. The endpoint path suggests it returns a payment schedule for a loan identified by ID 99, but the exact input parameters and response format are unknown. The `outputSchema` in the x402 challenge confirms the method is POST and the endpoint is discoverable, but provides no field-level detail.
Capabilities
Use cases
- —Generating an amortization schedule for a specific loan
- —Integrating loan payment breakdowns into fintech applications
- —Agent-driven financial planning that needs per-call loan schedule data
Fit
Best for
- —Developers needing on-demand loan schedule computation without subscription
- —AI agents that can pay per-call via x402/USDC on Base
- —Prototyping fintech tools with zero signup friction
Not for
- —Bulk loan portfolio analysis requiring thousands of calls (no volume discounts documented)
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/loans/99/schedule \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"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 beyond a wallet-connect prompt, and no examples. The endpoint path hints at loan schedule functionality but nothing is confirmed beyond the challenge metadata. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all show only 'Connect wallet'
- —No OpenAPI or JSON schema for request or response bodies
- —Endpoint path includes a hardcoded loan ID (99); unclear if this is parameterizable or a demo
- —No information on error handling, supported input fields, or response format
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/loans/99/schedule
- —Platform advertises $0.02 per request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/loans/99/schedule