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 protocol handles payment inline: callers attach a payment header to each request and receive the response immediately.
The specific endpoint at `/api/v1/transactions/167` is listed as "Premium API Access" and returns an x402 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 platform also advertises sibling 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 further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what this particular endpoint actually returns. The endpoint is live (402 challenge confirmed), but without documentation it is unclear what data or functionality "Premium API Access" at `/api/v1/transactions/167` actually provides.
Capabilities
Use cases
- —Accessing paid API endpoints without API key registration
- —Making one-off paid API calls settled in USDC on Base
- —Agent-driven programmatic access to various utility and data endpoints
Fit
Best for
- —Developers who want keyless, pay-per-use 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 schemas before integrating
- —High-volume consumers who want bulk pricing or subscription discounts
- —Developers who cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/167 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on what the endpoint actually does or returns. No OpenAPI spec, no request/response schemas, and all doc pages render only 'Connect wallet'. The listing title 'Premium API Access' is generic and uninformative.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The purpose of /api/v1/transactions/167 ('Premium API Access') is completely undocumented
- —Cannot verify what data or functionality this specific endpoint provides
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/167
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com