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/398` 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 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 uniformly priced at $0.02 per request.
However, documentation is extremely thin. 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/transactions/398` endpoint actually returns. The endpoint is live (402 challenge confirmed), but without documentation it is unclear what data or functionality this specific route provides.
Capabilities
Use cases
- —Accessing premium API data without traditional API key registration
- —Making one-off API calls paid directly in USDC on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
Fit
Best for
- —Developers who want to avoid API key management and subscriptions
- —AI agents that can settle x402 payments autonomously
- —Low-volume or sporadic API consumers who prefer per-call pricing
Not for
- —High-volume consumers who need bulk pricing or rate guarantees
- —Users who need detailed API documentation or SDKs before integrating
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/398 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is essentially no documentation — the docs, API, pricing, and README pages are all blank beyond a wallet-connect prompt. No OpenAPI schema, no request/response examples, and no explanation of what this specific endpoint returns. The listing is effectively a stub.
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 for /api/v1/transactions/398.
- —The purpose of the /api/v1/transactions/398 endpoint is unclear; 'Premium API Access' is a generic label with no further detail.
- —Cannot verify what data or functionality this endpoint actually provides.
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/398
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access.https://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories.https://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/transactions/398