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 at `/api/v1/portfolios/36` 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 and settled in USDC on the Base network.
The specific `/api/v1/portfolios/36` endpoint accepts POST requests and returns `application/json`. Payment is handled via the x402 exact-payment scheme: callers attach an `X-PAYMENT` header containing a signed USDC payment of up to 20,000 base units (i.e., $0.02 given USDC's 6 decimals) to the payee address `0x1A2B…85F3` on Base. No API keys, rate limits, or upfront commitments are required — each call is independently paid.
Because the endpoint path suggests a portfolio resource (ID 36), it likely returns portfolio-related data, but no OpenAPI schema, request body schema, or response examples are documented. The platform's docs, pricing, and API pages all render only a "Connect wallet" prompt with no further technical detail. Without additional documentation it is unclear what fields the POST body should contain or what the response payload looks like.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Integrating pay-as-you-go financial data into agent workflows without managing API keys
- —Programmatic access to portfolio resources settled on Base L2
Fit
Best for
- —Developers who want keyless, pay-per-call API access
- —AI agents with Base USDC wallets needing portfolio data
- —Prototyping x402-based payment flows
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who prefer subscription-based pricing
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/36 \
-H "X-PAYMENT: <signed-x402-payment-header>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and the docs pages are empty stubs showing only 'Connect wallet'. The purpose of the specific /portfolios/36 resource is undocumented.
Warnings
- —No OpenAPI or request/response schema available — callers must guess the POST body format
- —All documentation pages (docs, pricing, API, README) render only 'Connect wallet' with no technical content
- —The specific resource /api/v1/portfolios/36 is not listed on the homepage's API catalog, so its purpose is unclear
- —No rate-limit or SLA information provided
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/36
- —Platform advertises $0.02 per request, no API keys, no rate limits, Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/36
- —Docs, pricing, API, and README pages show only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs