Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
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 at `/api/v1/charges/309` is labeled "Premium API Access" and requires a payment of up to 20,000 base units of USDC (0.02 USD) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an x402 payment header to each request.
The broader platform offers endpoints across 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 utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02 per request price point.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what the `/api/v1/charges/309` endpoint actually returns. The endpoint is live (returns a valid 402 challenge), but without documentation it is unclear what data or functionality "Premium API Access" provides.
Capabilities
Use cases
- —Programmatic access to paid API endpoints without traditional API key registration
- —Agent-driven workflows that need on-demand API calls settled 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 can attach x402 payment headers autonomously
- —Users who want pay-as-you-go API access without subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Production workloads requiring well-documented request/response schemas
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/309 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only 'Connect wallet' with no useful content. The purpose of the specific /api/v1/charges/309 'Premium API Access' endpoint is entirely undocumented.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific endpoint /api/v1/charges/309 has no description beyond 'Premium API Access' — its actual functionality is unknown
- —No request/response examples available anywhere in crawled content
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/charges/309
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com