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 `/api/v1/transactions/256` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
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 $0.02 per request. However, the specific endpoint being listed here (`/api/v1/transactions/256`) does not clearly map to any of these advertised categories — its description is simply "Premium API Access" with no further documentation on what data or functionality it returns.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what this particular transactions endpoint actually does. Callers should be aware that the actual behavior of this endpoint is undocumented.
Capabilities
Use cases
- —Programmatic access to a pay-per-request API without needing API keys or subscriptions
- —Agent-driven workflows that settle per-call costs in USDC on Base
- —Exploring x402 protocol integration with low-cost endpoints
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing keyless, pay-as-you-go API access on Base
- —Low-cost per-request API consumption settled in USDC
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —High-volume use cases where per-request crypto settlement overhead matters
- —Anyone needing to understand the exact response schema before calling
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/256 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what this endpoint actually returns. No OpenAPI schema, no request/response examples, and the docs pages are empty. The endpoint path '/api/v1/transactions/256' with description 'Premium API Access' is opaque.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content
- —The endpoint '/api/v1/transactions/256' has no description of its actual functionality or response format
- —No OpenAPI or output schema provided beyond the basic x402 challenge metadata
- —This endpoint does not clearly map to any of the advertised API categories on the landing page
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/256
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/256
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com