Pay-per-call API platform on Base (USDC) covering 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 catalog of endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. 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 minimum commitments — callers simply attach an X-PAYMENT header to each request.
The specific endpoint at `/api/v1/transactions/124` 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 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 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 that need on-demand AI inference (sentiment, summarization, classification) without managing API keys
- —Fetching real-time crypto token quotes or gas estimates with per-call payment
- —Geocoding or data validation as a utility service within automated workflows
- —Exporting analytics data or generating reports on a pay-as-you-go basis
- —Prototyping applications that require diverse API capabilities without subscription commitments
Fit
Best for
- —AI agents needing keyless, pay-per-call access to diverse API endpoints
- —Developers prototyping with multiple API categories at minimal cost
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where per-request pricing adds up quickly
- —Users without a Base-compatible wallet or USDC holdings
- —Applications requiring detailed SLAs, guaranteed uptime, or dedicated support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/124 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'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 spec is available, and there are no request/response schemas or examples for any endpoint. The specific endpoint '/api/v1/transactions/124' has a generic 'Premium API Access' description with no detail on what it actually returns.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all returned only 'Connect wallet' with no usable content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific endpoint /api/v1/transactions/124 is not listed among the advertised endpoints on the landing page — its purpose is unclear
- —No request body schema or response schema is documented anywhere
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/transactions/124
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com