Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/keys/37` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each request.
The platform advertises four endpoint 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 listed endpoints share the same $0.02/request pricing.
The specific purpose of the `/api/v1/keys/37` endpoint is unclear from the available documentation — it is described only as "Premium API Access" and returns `application/json`. There is no OpenAPI spec, no request/response schema documentation, and the crawled /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no additional content. Callers should treat this as a minimally documented endpoint until more information is available.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API key registration
- —Agent-driven workflows that need on-demand API access settled in USDC on Base
- —Testing x402 payment flows against a live endpoint with low per-request cost
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402 protocol integrators looking for a live test endpoint
- —Users who prefer crypto-native micropayments over subscription billing
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/37 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schema, no examples, and the endpoint's actual functionality ("Premium API Access") is completely undocumented. The /api, /pricing, and /README pages returned no useful content.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown
- —The purpose of /api/v1/keys/37 ('Premium API Access') is not explained anywhere in the crawled material
- —Crawled /api, /pricing, and /README pages all returned only 'Connect wallet' with no documentation
- —Cannot verify what data or service this specific endpoint actually provides
Citations
- —Endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/37
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/37
- —Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com