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/2` is labeled "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, accounts, or rate limits are advertised — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API 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 utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point.
However, the specific endpoint being listed here (`/api/v1/charges/2`) does not clearly map to any of the named API categories on the landing page. Its description is simply "Premium API Access" with no further documentation on what data or functionality it returns. The docs, pricing, and README pages all rendered only a "Connect wallet" prompt with no additional content. Without documentation or example responses, the actual behavior of this endpoint is unknown.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint paid per-call with USDC on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need instant, keyless API access settled in USDC
- —Low-volume, pay-per-use API consumption without subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume use cases where $0.02/request adds up significantly
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/2 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what this specific endpoint actually does or returns. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. No OpenAPI spec, no example requests or responses, and the endpoint path '/api/v1/charges/2' doesn't match any of the named APIs on the landing page.
Warnings
- —No documentation available — docs, pricing, and README pages only show 'Connect wallet'
- —The endpoint path /api/v1/charges/2 does not correspond to any named API on the landing page
- —No OpenAPI spec or output schema describing what this endpoint returns
- —Actual functionality of 'Premium API Access' is completely undocumented
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x8335…) on Base networkhttps://lowpaymentfee.com/api/v1/charges/2
- —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 advertises categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com