Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
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/6` 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 uniformly priced at $0.02 per request.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The endpoint is live and responds with a valid x402 challenge, but without documentation it is unclear what request body the `/api/v1/transactions/6` endpoint expects or what it returns.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Integrating pay-as-you-go API calls into agent workflows without managing API keys
- —Making one-off transaction queries with instant crypto settlement
Fit
Best for
- —Developers who want keyless, pay-per-use API access
- —Agent systems that can attach x402 payment headers automatically
- —Users already holding USDC on the Base network
Not for
- —Teams needing detailed API documentation or OpenAPI specs before integration
- —Users without USDC on the Base network or unfamiliar with x402 protocol
- —High-volume use cases where per-request pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/6 \
-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, documentation is essentially nonexistent — no OpenAPI spec, no request/response schemas, no examples, and the docs pages are empty. The purpose of the specific '/transactions/6' endpoint is unclear beyond its title 'Premium API Access'.
Warnings
- —No OpenAPI specification or schema documentation available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The specific purpose and expected request/response format of /api/v1/transactions/6 is undocumented
- —No examples or sample payloads are provided anywhere on the site
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/6
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all priced at $0.02/requesthttps://lowpaymentfee.com
- —The platform advertises no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/6