Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are paid per-request at $0.02 each using USDC on the Base network, with no API keys, rate limits, or subscriptions 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/14` 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 payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
The broader platform advertises endpoints in 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 beyond the landing page were largely empty (showing only "Connect wallet"), so detailed request/response schemas for individual endpoints are not available.
Capabilities
Use cases
- —Agents making one-off API calls without needing to register or manage API keys
- —Paying for AI inference (sentiment, summarization, classification, embeddings) per request with USDC
- —Fetching real-time crypto prices, gas estimates, or exchange rates on demand
- —Geocoding or data validation as a utility service with no subscription commitment
Fit
Best for
- —AI agents that need keyless, pay-per-call access to diverse API endpoints
- —Developers prototyping with low-cost, no-commitment API access
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads needing bulk pricing or SLAs
- —Users without access to USDC on the Base network
- —Applications requiring detailed API documentation or guaranteed uptime
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/14 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint works and pricing is clear ($0.02 USDC on Base). However, documentation pages are effectively empty, no OpenAPI schema is available, and there are no request/response examples for any endpoint. The specific purpose of /api/v1/transactions/14 beyond 'Premium API Access' is unclear.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only 'Connect wallet' with no actual content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific function of /api/v1/transactions/14 is not documented — 'Premium API Access' is vague
- —Request and response body schemas are unknown; callers must discover them experimentally
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —x402 challenge requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/14
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Payment scheme is 'exact' with maxTimeoutSeconds of 300https://lowpaymentfee.com/api/v1/transactions/14