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 data, and utility services. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/transactions/138` is listed as "Premium API Access" and its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. The platform also exposes endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — 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 schema, no request/response examples, and no description of what the `/api/v1/transactions/138` endpoint actually returns. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is unclear what data or functionality this specific route provides.
Capabilities
Use cases
- —Accessing API endpoints without creating accounts or managing API keys
- —Making one-off paid API calls from autonomous agents using x402
- —Paying for data or AI inference per-request with USDC on Base
Fit
Best for
- —Agents that need frictionless pay-per-call API access without signup
- —Developers experimenting with x402 payment protocol integrations
- —Use cases requiring low-cost, no-commitment API calls
Not for
- —Production workloads requiring documented, stable API contracts
- —Users who need detailed request/response schemas before integrating
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/138 \
-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 this specific endpoint does, what inputs it accepts, or what it returns. The docs/pricing/README pages are all blank beyond a wallet connect prompt. Effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet'
- —No OpenAPI schema or request/response examples provided
- —The purpose of /api/v1/transactions/138 ('Premium API Access') is completely undocumented — unclear what data or service it provides
- —Cannot verify what the endpoint actually returns upon successful payment
Citations
- —All endpoints priced at $0.02 per request, no API keys, no rate limits, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/138
- —Endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com