x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at lowpaymentfee.com exposes a portfolio resource (`/api/v1/portfolios/93`) behind an x402 payment challenge. It is part of a broader platform that offers data & analytics, AI/ML inference, finance/Web3 data, and infrastructure utility endpoints, all priced at $0.02 per request settled in USDC on the Base network.
The specific `/api/v1/portfolios/93` endpoint accepts POST requests and returns `application/json`. Payment is handled via the x402 exact-payment scheme: the caller includes an `X-PAYMENT` header containing a signed USDC transfer of up to 20,000 base units (i.e., $0.02, since USDC uses 6 decimals) to the provider's address on Base. No API keys, subscriptions, or rate limits are advertised — access is purely pay-per-call.
Documentation beyond the landing page is extremely thin. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI spec, no request/response schema, and no explanation of what the "portfolios/93" resource actually contains or what POST body it expects. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation the actual data returned and required input format remain unknown.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Integrating pay-per-call financial data into autonomous agents
- —Accessing premium data without managing API keys or subscriptions
Fit
Best for
- —Agents or apps that can sign x402 USDC payments on Base
- —Developers wanting key-less, pay-as-you-go API access
- —Low-volume or sporadic consumers who prefer no subscription commitment
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone unable to transact in USDC on the Base L2 network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/93 \
-H "X-PAYMENT: <signed-x402-payment-header>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation of what the portfolios/93 resource returns, and all doc pages render only 'Connect wallet'. The listing is effectively a stub with confirmed liveness.
Warnings
- —No OpenAPI or schema available — request body format and response structure are completely unknown.
- —All documentation pages (docs, API, pricing, README) return only a 'Connect wallet' prompt with no technical content.
- —The specific resource '/api/v1/portfolios/93' is not listed on the provider's landing page; its purpose is unclear.
- —Cannot verify what data is actually returned without making a paid request.
Citations
- —The endpoint returns a 402 challenge with x402Version 1, exact scheme, USDC on Base, maxAmountRequired 20000https://lowpaymentfee.com/api/v1/portfolios/93
- —Platform pricing is $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/93