x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys needed.
What it does
This endpoint at lowpaymentfee.com exposes a portfolio resource at `/api/v1/portfolios/39` behind an x402 payment challenge. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility APIs, all priced at $0.02 per request settled in USDC on the Base network.
The specific resource at `/portfolios/39` is labeled "Premium API Access" in the x402 challenge. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02. Payment is made via the x402 exact scheme — callers attach an `X-PAYMENT` header with a signed payment proof, and the endpoint returns the requested JSON payload. No API keys, accounts, or rate limits are advertised; access is purely pay-per-call.
Because the crawled documentation pages (`/docs`, `/api`, `/pricing`, `/README`) all returned only a "Connect wallet" stub with no further content, the actual schema of the response body, accepted POST parameters, and the nature of the "portfolio" data are unknown. The landing page confirms the platform's general categories (analytics, AI, finance, infrastructure) and uniform $0.02 pricing, but provides no specifics about this particular endpoint's input or output format. Treat this listing as a stub until richer documentation becomes available.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Agent-driven data retrieval without managing API keys or subscriptions
- —Integrating pay-as-you-go financial data into automated workflows
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Applications requiring non-crypto (fiat-only) payment rails
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/39 \
-H "X-PAYMENT: <x402-signed-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but all documentation pages are empty stubs. No input/output schema, no example responses, and the purpose of the 'portfolios/39' resource is unexplained. Effectively a stub listing.
Warnings
- —All documentation pages (/docs, /api, /pricing, /README) returned only 'Connect wallet' with no usable content.
- —No input or output schema is available for this endpoint — the POST body format and response structure are unknown.
- —The nature of the 'portfolio' data returned by /api/v1/portfolios/39 is not documented anywhere in the crawl.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base network, equaling $0.02.https://lowpaymentfee.com/api/v1/portfolios/39
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —Documentation pages /docs, /api, /pricing, /README all returned only 'Connect wallet' stubs.https://lowpaymentfee.com/docs