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 provides a "Premium API Access" resource at `/api/v1/portfolios/12` via the x402 payment protocol. The endpoint is live and returns a 402 challenge requesting payment in USDC on the Base network. The price per request is $0.02 (20,000 base units of USDC with 6 decimals). Payment is made via the x402 `exact` scheme, settling to the specified wallet address, with a maximum timeout of 300 seconds.
The broader lowpaymentfee.com platform advertises a wide catalog of pay-per-call APIs spanning data & analytics, AI & machine learning (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request with no API keys, no rate limits, and no commitments.
However, the specific `/api/v1/portfolios/12` endpoint is not explicitly listed on the site's landing page catalog, and there is no documentation describing what data it returns. The docs, pricing, and API pages all render only a "Connect wallet" prompt with no further content. Without an OpenAPI schema, example responses, or documentation for this particular resource, the exact payload and use case remain unclear. The endpoint appears to be part of a portfolio or financial data service, but this is inferred solely from the URL path.
Capabilities
Use cases
- —Fetching portfolio data (likely financial) via a single paid API call
- —Agent-driven data retrieval with automatic USDC micropayment on Base
- —Accessing premium data without traditional API key registration
Fit
Best for
- —Agents or services that can settle x402 payments in USDC on Base
- —Developers wanting keyless, pay-per-call API access
- —Micropayment-based data consumption without subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Applications requiring free or fiat-only payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/12 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no OpenAPI schema, no documentation, no example responses, and the specific /portfolios/12 resource is not even listed on the provider's own landing page. The docs/pricing/API pages are all blank beyond a wallet connect prompt. Effectively a stub with confirmed liveness.
Warnings
- —The /api/v1/portfolios/12 endpoint is not listed in the provider's own API catalog on the landing page — its purpose is unclear.
- —All documentation pages (docs, pricing, API, README) render only 'Connect wallet' with no usable content.
- —No OpenAPI schema, no example request/response, and no description of the response payload are available.
- —The broader platform lists many endpoints but none have visible documentation — treat with caution.
Citations
- —The endpoint returns a 402 challenge requesting USDC payment on Base with maxAmountRequired of 20000 base units (=$0.02)https://lowpaymentfee.com/api/v1/portfolios/12
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/12
- —Docs, pricing, API, and README pages show only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs