x402-gated portfolio data endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at `/api/v1/portfolios/66` 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/66` resource is listed under "Premium API Access" but its exact data payload is not documented in the available crawl material. The platform advertises a flat $0.02 per request pricing model with no API keys, no rate limits, and instant access.
Payment is settled on the Base network using USDC (contract `0x8335…2913`) via the x402 exact-payment scheme. The probe confirmed a live 402 challenge with `maxAmountRequired` of 20,000 base units, which at 6 decimals equals $0.02 — consistent with the site's advertised pricing. The endpoint accepts POST requests and returns `application/json`. No OpenAPI schema, detailed documentation, or example responses were found; the docs, pricing, and README pages all rendered only a "Connect wallet" prompt with no substantive content.
Because the actual response schema and the meaning of "portfolios/66" are undocumented, agents should treat this as a low-information endpoint. The platform appears to be a demonstration or early-stage x402 API marketplace. Use with caution until richer documentation is available.
Capabilities
Use cases
- —Fetching portfolio data behind a per-request USDC paywall
- —Demonstrating x402 payment protocol integration on Base
- —Agent-driven data retrieval without API key management
Fit
Best for
- —Developers experimenting with x402 payment flows
- —Agents that can settle USDC payments on Base
- —Low-cost per-request data access without subscriptions
Not for
- —Production use requiring documented response schemas
- —High-throughput bulk data retrieval where per-call cost adds up
- —Users who need fiat-only payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/66 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing, but there is no documentation, no OpenAPI schema, no example responses, and the purpose of '/portfolios/66' is unexplained. Docs pages are empty beyond a wallet-connect prompt. Effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, and README pages only show 'Connect wallet' with no content
- —Response schema for /api/v1/portfolios/66 is completely undocumented; actual payload is unknown
- —The platform appears to be early-stage or a demo; reliability and data quality are unverified
- —The specific meaning of 'portfolios/66' (what portfolio, what data) is not described anywhere
Citations
- —Flat $0.02 per request pricing with no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/66
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/66