Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/charges/37` is listed as "Premium API Access" and costs $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — each request is paid individually via an X-PAYMENT header.
The broader platform advertises multiple API categories including 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 listed at the same $0.02/request price point and settle in USDC on Base.
However, the specific endpoint being listed here (`/api/v1/charges/37`) is labeled only as "Premium API Access" with no further documentation about what data or functionality it returns. The docs, pricing, and API pages on the site all render only a "Connect wallet" prompt with no additional content. Without schema details or example responses, the actual behavior of this endpoint is unknown.
Capabilities
Use cases
- —Programmatic access to a paid API endpoint without needing API key registration
- —Agent-driven workflows that settle per-call payments in USDC on Base
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that need keyless, pay-per-use API access
- —Users who want to avoid subscription commitments for occasional API calls
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —High-volume use cases where per-request pricing may add up without bulk discounts
- —Anyone who needs to understand the exact response schema before calling
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/37 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (returns 402 as expected for x402), and pricing is clear ($0.02 USDC on Base). However, there is no documentation, no OpenAPI schema, no example request/response, and the docs pages are empty ('Connect wallet' only). The specific functionality of /api/v1/charges/37 is completely undocumented — it's unclear what 'Premium API Access' actually provides.
Warnings
- —No documentation available — docs, pricing, and API pages all show only 'Connect wallet'
- —The specific endpoint /api/v1/charges/37 has no description of what it returns or what input it expects
- —No OpenAPI schema or example responses are provided
- —The endpoint path '/charges/37' does not match any of the advertised API categories on the homepage, making its purpose unclear
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 in USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/charges/37
- —All listed APIs are priced at $0.02/request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com