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 broad set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required. The specific endpoint at `/api/v1/transactions/7` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02, since USDC uses 6 decimals) on Base.
The platform advertises four categories of APIs: 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 (geocoding, validation, conversion, generation). All endpoints follow the x402 payment protocol — callers send an `X-PAYMENT` header with a signed payment to the provider's address on Base, and receive the API response upon successful settlement.
Documentation is extremely sparse. The docs, API, pricing, 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 detailed documentation for any endpoint. The actual behavior and output format of `/api/v1/transactions/7` (or any other endpoint) cannot be determined from available materials.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token prices, exchange rates, and gas estimates on a per-call basis
- —Running data analytics queries and exporting data with per-request USDC micropayments
- —Using utility services like geocoding, validation, and conversion via x402 payment
Fit
Best for
- —Agents or developers who want zero-signup, pay-per-call API access
- —Use cases requiring micropayment-gated endpoints on Base L2
- —Projects that need a variety of lightweight API services without rate limits
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Applications requiring high-throughput bulk access at lower per-unit cost
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/7 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and the purpose of '/api/v1/transactions/7' specifically is unclear beyond the generic 'Premium API Access' label. The platform lists many endpoints but provides no detail on any of them.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no usable content
- —No OpenAPI or schema available for any endpoint
- —The specific purpose and expected input/output of /api/v1/transactions/7 is unknown — 'Premium API Access' is not descriptive
- —No request or response examples available anywhere in crawled materials
- —Cannot verify that any of the advertised API categories actually return meaningful data
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC on Base (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)https://lowpaymentfee.com/api/v1/transactions/7
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Documentation pages render only a 'Connect wallet' prompt with no further contenthttps://lowpaymentfee.com/docs