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/transactions/390` 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 — you 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/request price point.
This particular endpoint (`/api/v1/transactions/390`) is labeled generically as "Premium API Access" and does not appear in the main site's listed API catalog. There is no documentation describing what data or functionality it returns. The docs, pricing, and API pages all render only a "Connect wallet" prompt with no further content. Without additional documentation or an OpenAPI schema, the actual behavior of this endpoint remains unclear.
Capabilities
Use cases
- —Programmatic access to paid API endpoints without managing API keys or subscriptions
- —Agent-driven workflows that need to pay per call using on-chain USDC on Base
- —Accessing premium data or services with micropayments
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Anyone without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/390 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge), but there is no OpenAPI schema, no documentation beyond a landing page, no examples, and the specific endpoint is not listed in the site's own catalog. The actual functionality behind 'Premium API Access' is completely undocumented.
Warnings
- —The endpoint /api/v1/transactions/390 does not appear in the site's own listed API catalog — its purpose is unknown.
- —All documentation pages (docs, pricing, API, README) render only 'Connect wallet' with no usable content.
- —No OpenAPI schema, request/response examples, or detailed endpoint descriptions are available.
- —The actual data or service returned by this endpoint is undocumented and cannot be verified.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base network.https://lowpaymentfee.com/api/v1/transactions/390
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access.https://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/transactions/390
- —The site lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories.https://lowpaymentfee.com