x402-gated premium API access on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol on the Base network. The specific resource `/api/v1/portfolios/58` is one of many endpoints offered by the platform, which spans categories including data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. All endpoints on the platform share a uniform $0.02-per-request pricing model settled in USDC (USD Coin) on Base, with no API keys, no rate limits, and no minimum commitments required.
The x402 challenge confirms the endpoint is live, accepting POST requests and requiring an X-PAYMENT header with an exact payment scheme. The max amount required is 20,000 base units of USDC (0x8335…2913 on Base), which at 6 decimals equals $0.02 per call. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
However, the specific functionality of the `/api/v1/portfolios/58` endpoint is not documented on the site's landing page or any crawled page. The site lists various API categories (analytics, AI, finance, infrastructure) but does not mention a "portfolios" endpoint. No request/response schema, input parameters, or example outputs are available for this particular resource. The docs, pricing, and README pages all rendered only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Fetching portfolio data (portfolio ID 58) via a single paid API call
- —Integrating pay-per-request data access into agent workflows without API key management
- —Programmatic access to premium data behind x402 micropayment gates
Fit
Best for
- —Agents or developers who want keyless, pay-per-call API access
- —Users already holding USDC on Base who need low-friction data endpoints
- —Scenarios requiring no subscription commitments or rate limit concerns
Not for
- —Users who need detailed documentation or schema guarantees before integrating
- —High-volume consumers who would prefer bulk pricing or subscriptions
- —Anyone without USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/58 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what /api/v1/portfolios/58 actually returns. No request schema, no response schema, no examples, and the crawled docs/pricing/README pages are empty. The specific 'portfolios' resource is not even listed on the site's landing page.
Warnings
- —The /api/v1/portfolios/58 endpoint is not listed among the site's advertised APIs — its purpose and response format are unknown.
- —All documentation pages (docs, pricing, README, api) returned only a 'Connect wallet' prompt with no usable content.
- —No request or response schema is available for this endpoint.
- —The platform appears to be a generic x402 demo or showcase site; the actual data quality and reliability behind these endpoints is unverified.
Citations
- —Uniform $0.02 per request pricing, no API keys, no rate limits, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/portfolios/58
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with 300-second timeouthttps://lowpaymentfee.com/api/v1/portfolios/58