Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data & analytics, AI & machine learning, finance & Web3, and infrastructure/utility categories. All endpoints are priced at $0.02 per request, paid in USDC on the Base network. The platform uses the x402 payment protocol, meaning no API keys, accounts, or rate limits are required — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/charges/130` is listed as "Premium API Access" and accepts POST requests. The x402 challenge indicates a maximum amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is settled to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a timeout of 300 seconds.
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. However, documentation beyond the landing page is essentially empty (all sub-pages just show "Connect wallet"), so the actual behavior, input/output schemas, and data sources for each endpoint are unknown.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification) without managing API keys
- —Fetching real-time crypto token quotes or gas estimates via micropayment
- —Geocoding or data validation as a utility service with per-call billing
- —Exporting analytics data or generating insights on a pay-as-you-go basis
Fit
Best for
- —AI agents that need keyless, pay-per-call access to diverse utility endpoints
- —Developers prototyping with low-commitment, no-signup API access
- —Web3-native applications already holding USDC on Base
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/130 \
-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 lists available APIs with pricing. However, all documentation pages are empty ('Connect wallet' only), there is no OpenAPI schema, no input/output examples, and the actual functionality of '/api/v1/charges/130' ('Premium API Access') is completely undocumented. The listing is effectively a stub with pricing info.
Warnings
- —All documentation pages (/docs, /api, /pricing, /README) return no useful content — just 'Connect wallet'
- —No OpenAPI or schema available; input parameters and response format for this endpoint are unknown
- —The endpoint path '/api/v1/charges/130' with description 'Premium API Access' does not match any of the advertised API categories on the landing page — its actual function is unclear
- —No information about data sources, model providers, or accuracy guarantees for any of the advertised capabilities
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, 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/130
- —Platform advertises endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com