Pay-per-call API platform on Base via x402 — $0.02/request for data, AI, finance, and utility endpoints.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint at `/api/v1/payments/350` is labeled "Premium API Access" and costs $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — each request is paid for individually via an X-PAYMENT header containing a signed x402 payment.
The broader platform advertises multiple API categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All listed endpoints share the same $0.02/request pricing.
Documentation is extremely sparse. The docs, API reference, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what the `/api/v1/payments/350` endpoint specifically returns. The x402 challenge confirms the endpoint is live and accepts POST requests, but the actual functionality behind this particular path is unclear.
Capabilities
Use cases
- —Agents needing on-demand API access without signup or API key management
- —Paying per-call for data analytics, AI inference, or financial data via crypto micropayments
- —Testing x402 protocol integrations on the Base network
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents with USDC on Base that need frictionless endpoint access
- —Prototyping x402 payment flows at low cost ($0.02/call)
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume production workloads where per-request crypto payments add overhead
- —Users without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/350 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The x402 challenge confirms the endpoint is live and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no request/response examples, and no explanation of what this specific endpoint actually does. The docs pages are empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific functionality of /api/v1/payments/350 ('Premium API Access') is undocumented and unclear
- —No request or response examples available anywhere in crawled content
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/350
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/payments/350