Pay-per-call API platform on Base via x402 — data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints across four 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 endpoints are priced at $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/charges/1` is described as "Premium API Access" and returns a standard x402 challenge requesting payment of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. Payment is settled on-chain via the x402 exact scheme. The endpoint accepts HTTP POST requests and returns application/json responses.
Documentation beyond the landing page 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 example payloads available. It is unclear what specific data or functionality the `/api/v1/charges/1` endpoint returns, as the landing page lists it under none of the named API categories. Prospective users should be aware that the actual behavior of individual endpoints is undocumented.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without subscription or API key
- —Fetching real-time financial data such as token quotes, exchange rates, and gas estimates on a per-call basis
- —Running utility operations like geocoding, validation, and data conversion with instant crypto-settled payments
- —Exporting analytics data and insights via pay-per-request model
Fit
Best for
- —Agents or bots that need stateless, pay-per-call API access without managing API keys
- —Developers prototyping with low-cost, no-commitment API endpoints
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —Users who need detailed API documentation, request/response schemas, or SLA guarantees
- —High-volume production workloads where per-request crypto settlement overhead is impractical
- —Users without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/1 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, and the landing page provides a catalog of endpoints with pricing. However, there is no OpenAPI spec, no request/response documentation, no example payloads, and the specific /api/v1/charges/1 endpoint's purpose is unclear. All secondary pages render only 'Connect wallet' with no content.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages are empty beyond a wallet connect prompt
- —No OpenAPI or schema definition found for any endpoint
- —The specific endpoint /api/v1/charges/1 is not listed among the named APIs on the landing page; its actual functionality is unknown
- —No request or response examples are available anywhere in the crawled content
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/charges/1
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Docs, pricing, api, and README pages render only 'Connect wallet'https://lowpaymentfee.com/docs