x402-gated portfolio endpoint on Base, pay-per-call with USDC at $0.02/request.
What it does
This endpoint at `/api/v1/portfolios/13` is part of the lowpaymentfee.com platform, which offers a collection of x402-protocol pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. The specific `/portfolios/13` resource is listed under "Premium API Access" and accepts POST requests gated by an x402 payment challenge. Payment is settled in USDC on the Base network.
The x402 challenge advertises a `maxAmountRequired` of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02 per request. The platform's landing page confirms a flat $0.02/request pricing model across all endpoints, with no API keys, no rate limits, and no minimum commitments required. The endpoint returns `application/json` responses.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what the `/portfolios/13` resource actually returns. The endpoint name "Premium API Access" is generic and does not clarify the data served. Based on the site's category groupings (Data & Analytics, AI & ML, Finance & Web3, Infrastructure), this portfolio endpoint likely returns some form of structured data, but its exact purpose cannot be confirmed from available materials.
Capabilities
Use cases
- —Accessing portfolio data via a single pay-per-request call without subscription or API key
- —Agent-driven workflows that need on-demand data retrieval with crypto micropayments
- —Integrating low-friction paid API calls settled on Base L2 in USDC
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents with x402 payment capability on Base
- —Users who prefer crypto micropayments over traditional API billing
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/13 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is zero documentation on what the /portfolios/13 resource actually returns. No OpenAPI schema, no request body specification, no response examples. The docs/pricing/README pages are all empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema describing request parameters or response format for /portfolios/13
- —The endpoint name 'Premium API Access' is generic and does not describe the actual data returned
- —Cannot confirm what 'portfolios/13' represents — the resource purpose is unknown
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/13
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/13
- —Platform pricing is $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Docs, pricing, API, and README pages render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs