Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The specific resource `/api/v1/invoices/47` is one of many endpoints offered by the platform, which spans data & analytics, AI & machine learning, finance & Web3, and infrastructure utility categories. All endpoints are priced at $0.02 per request, settled in USDC on the Base network, 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 exact payment of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The response MIME type is application/json.
The broader platform advertises endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. However, documentation pages (/docs, /pricing, /api, /README) all returned only a "Connect wallet" prompt with no substantive content, so the actual behavior and response schemas of these endpoints remain undocumented and unverified.
Capabilities
Use cases
- —Accessing premium API data without needing API key registration
- —Making one-off paid API calls settled in USDC on Base
- —Agent-driven workflows that need instant, keyless API access
Fit
Best for
- —Developers who want zero-friction pay-per-call API access
- —AI agents that can settle x402 payments autonomously
- —Users already holding USDC on the Base network
Not for
- —Users needing detailed API documentation or response schemas before purchasing
- —Anyone without USDC on Base or an x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/invoices/47 \
-H "X-PAYMENT: <x402-payment-header>" \
-H "Content-Type: application/json"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no documented request/response format, and all documentation pages return only a wallet-connect prompt. The specific purpose of /api/v1/invoices/47 is unclear beyond the generic label "Premium API Access."
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README all return only 'Connect wallet' with no content.
- —The specific behavior and response schema of /api/v1/invoices/47 is unknown; the endpoint name suggests invoice data but nothing confirms this.
- —The platform lists many endpoint categories (AI, finance, analytics, etc.) but none have documented schemas or example responses.
Citations
- —Endpoint returns 402 with x402 challenge requiring 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/invoices/47
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/invoices/47
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com