x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys needed.
What it does
This endpoint at lowpaymentfee.com exposes a portfolio resource at `/api/v1/portfolios/11` behind an x402 payment wall. It is part of a broader platform offering dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request, settled in USDC on the Base network.
The specific `/api/v1/portfolios/11` endpoint accepts POST requests and returns JSON. The x402 challenge advertises a max amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. No API keys or accounts are required; callers simply attach an X-PAYMENT header with a valid x402 payment proof.
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 explanation of what the "portfolios/11" resource actually returns. The endpoint is live (402 challenge confirmed), but without documentation it is difficult to know what data to POST or what response to expect.
Capabilities
Use cases
- —Fetching portfolio data via a single micropayment without needing an API key
- —Agent-driven programmatic access to portfolio resources with on-chain USDC settlement
- —Integrating low-cost pay-per-request data endpoints into automated workflows
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who want bulk pricing or subscription plans
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/11 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is zero documentation on request format, response schema, or what 'portfolios/11' actually provides. No OpenAPI spec, no examples, and all doc pages are empty. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet' with no content
- —No OpenAPI or schema definition found for this endpoint
- —Unknown request body format — no input schema documented
- —Unknown response format — no output schema or examples available
- —The specific resource 'portfolios/11' is not listed on the landing page; only analytics, AI, finance, and utility endpoints are advertised
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/11
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/11