Pay-per-call premium API on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
This endpoint at lowpaymentfee.com/api/endpoint-39 is an x402-gated "Premium API Access" service settling payments in USDC on the Base network. The site advertises a broad catalog of API categories — data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request. However, this specific endpoint (/api/endpoint-39) is not listed among the documented routes on the landing page, so its exact functionality is unclear. The x402 challenge confirms it is live, accepts POST requests, and returns application/json.
The payment challenge specifies a maxAmountRequired 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 using the "exact" scheme with a 300-second timeout. No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
Documentation beyond the landing page is essentially empty (all sub-pages just show "Connect wallet"), so there is no schema documentation, example requests/responses, or detailed descriptions of what this particular endpoint returns. The site lists many endpoints across multiple domains (sentiment analysis, summarization, geocoding, price feeds, etc.) but /api/endpoint-39 does not map to any of them. Treat this as a stub listing until more documentation becomes available.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint with per-call USDC micropayments
- —Agent-driven workflows that need keyless, on-demand API access on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can settle USDC payments on Base L2
- —Use cases requiring no-signup, pay-as-you-go API access
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone needing a specific, well-documented capability (endpoint purpose is unclear)
- —Non-crypto users without Base USDC wallets
Quick start
curl -X POST https://lowpaymentfee.com/api/endpoint-39 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Example
Request
{}Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but this specific endpoint (/api/endpoint-39) is not documented anywhere on the site. All documentation pages are empty stubs showing only 'Connect wallet'. No input/output schema, no examples, and no description of what the endpoint actually does.
Warnings
- —Endpoint /api/endpoint-39 is not listed among the documented API routes on the landing page — its purpose is unknown.
- —All documentation pages (/docs, /api, /pricing, /README) are empty, showing only 'Connect wallet'.
- —No OpenAPI spec, input schema, or response examples are available.
- —Unclear whether this endpoint is a placeholder, test route, or serves a specific function.
Citations
- —The site lists APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categories, all at $0.02/request.https://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —x402 challenge confirms live 402 response with maxAmountRequired of 20000 base units of USDC on Base.https://lowpaymentfee.com/api/endpoint-39