Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, payable in USDC on the Base network with no API keys, no rate limits, and no commitments required. The x402 payment protocol allows agents and clients to pay per call by attaching a payment header to each HTTP request.
The specific endpoint at `/api/v1/transactions/396` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and returns application/json. The broader platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and data export — all at the same $0.02 price point.
Documentation is extremely sparse. The docs, pricing, API, 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 detailed descriptions of what each endpoint actually returns. The platform appears live (root returns 200, x402 challenge is valid), but without documentation it is difficult to assess the actual quality or content of responses.
Capabilities
Use cases
- —Paying per-request for API access without subscriptions or API keys
- —Agent-driven workflows that need on-demand data, AI inference, or utility endpoints
- —Programmatic access to analytics, finance, or ML endpoints settled in USDC on Base
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents with x402-compatible payment capabilities
- —Users who prefer crypto-native micropayments over traditional billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where $0.02/request adds up significantly
- —Users without USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/396 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC per call on Base). However, documentation is essentially nonexistent — all doc/pricing/API pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and no description of what this specific 'Premium API Access' endpoint actually does or returns. The endpoint path '/api/v1/transactions/396' with a numeric ID is opaque without further context.
Warnings
- —No documentation available — all doc pages render only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The endpoint path /api/v1/transactions/396 is not listed among the advertised APIs on the homepage, making its purpose unclear
- —No request or response examples available anywhere in crawled content
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/396
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com