x402-gated portfolio endpoint on Base, pay-per-request with USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" at the path `/api/v1/portfolios/35`. It is part of a broader platform offering dozens of pay-per-call API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated via the x402 payment protocol on the Base network.
The specific `/api/v1/portfolios/35` endpoint accepts POST requests and returns JSON. Payment is settled in USDC (contract `0x8335…2913` on Base) at a maximum cost of $0.02 per request (20,000 base units with 6 decimals). The platform advertises no API keys, no rate limits, and instant access — you simply attach an x402 payment header to each call. The payment timeout is 300 seconds.
Documentation is extremely sparse. The landing page lists available endpoints and pricing, but the `/docs`, `/pricing`, `/api`, and `/README` pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no description of what the "portfolios/35" resource actually returns. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is unclear what data or functionality this specific portfolio endpoint provides.
Capabilities
Use cases
- —Fetching portfolio data via a single micropayment without API key registration
- —Integrating pay-per-request portfolio access into an autonomous agent workflow
- —Accessing premium data endpoints using on-chain USDC payments on Base
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation before integrating
- —High-volume consumers who want bulk pricing or subscriptions
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/35 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation, no OpenAPI spec, no request/response schema, and no explanation of what the portfolios/35 resource actually returns. The docs, pricing, and 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 definition found for this endpoint
- —The purpose and response format of /api/v1/portfolios/35 is completely undocumented
- —No agents.txt or robots.txt found
Citations
- —The endpoint returns a 402 challenge with x402Version 1, accepting USDC on Base network at maxAmountRequired 20000https://lowpaymentfee.com/api/v1/portfolios/35
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/35