Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint is priced at $0.02 per request, paid in USDC on the Base network via the x402 payment protocol. There are no API keys, no rate limits, and no sign-up — callers simply attach an X-PAYMENT header with a valid x402 payment proof to access any endpoint.
The specific endpoint at `/api/v1/payments/293` is listed as "Premium API Access" and returns JSON. The x402 challenge advertises a maxAmountRequired of 20000 base units of USDC (contract 0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform's landing page lists 16 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 (geocoding, validation, conversion, generation). Documentation pages were largely empty (showing only "Connect wallet"), so the actual request/response schemas for individual endpoints are unknown.
Capabilities
Use cases
- —Querying real-time crypto token quotes and gas estimates without an API key
- —Running sentiment analysis or text summarization on demand with per-call USDC payment
- —Fetching exchange rates or price feeds for financial applications
- —Geocoding addresses or validating data via utility endpoints
Fit
Best for
- —Developers who want instant API access without sign-up or API key management
- —Agents and bots that can settle micropayments in USDC on Base
- —Low-volume or bursty workloads where flat per-request pricing is cost-effective
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs
- —Callers who cannot settle payments in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/293 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation beyond a landing page listing, no request/response examples, and the specific purpose of the /api/v1/payments/293 endpoint ("Premium API Access") is vague. Docs pages returned only 'Connect wallet' with no content.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are effectively empty — only showing 'Connect wallet'
- —No OpenAPI or schema available; request and response formats for all endpoints are unknown
- —The specific function of /api/v1/payments/293 ('Premium API Access') is unclear and may be a generic or placeholder endpoint
- —No information on uptime, SLAs, rate limits, or data sources
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 with 300-second timeouthttps://lowpaymentfee.com/api/v1/payments/293
- —Platform offers 16 endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com