Pay-per-request API platform on Base network via x402 — $0.02/call 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/380` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals) per call. No API keys or rate limits are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
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. However, the specific endpoint probed (`/api/v1/charges/380`) does not clearly map to any of these named services — it may be a generic or catch-all premium access route.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what data or functionality the `/api/v1/charges/380` endpoint actually returns. The endpoint is confirmed live (402 challenge captured), but without documentation it is unclear what payload to send or what response to expect.
Capabilities
Use cases
- —Paying per-request for API access without managing API keys or subscriptions
- —Integrating USDC-settled micropayments into automated agent workflows
- —Accessing data analytics, AI inference, or financial data endpoints on a pay-as-you-go basis
Fit
Best for
- —Developers wanting zero-commitment, pay-per-use API access
- —AI agents with x402-compatible payment capabilities on Base
- —Users who prefer crypto micropayments over traditional billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who need bulk pricing or SLAs
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/380 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, documentation is essentially nonexistent — no OpenAPI schema, no request/response examples, and no explanation of what the endpoint actually does beyond the label "Premium API Access." The specific path /api/v1/charges/380 doesn't correspond to any documented service.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema describing request parameters or response format
- —The endpoint path /api/v1/charges/380 does not match any of the advertised API routes on the homepage
- —Cannot determine what data or functionality this specific endpoint provides
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/380
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/380
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform advertises categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com