Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint `/api/v1/keys/14` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — no API keys, accounts, or subscriptions are required; callers attach an X-PAYMENT header to each request.
The wider 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 with no rate limits or minimum commitments.
Important caveat: the specific functionality behind `/api/v1/keys/14` ("Premium API Access") is not documented beyond its title. There is no OpenAPI schema, no request/response examples, and the crawled docs pages (pricing, README, /api) returned only a "Connect wallet" prompt with no additional content. Prospective callers should test the endpoint to determine what data or service it actually returns.
Capabilities
Use cases
- —Agent-driven data retrieval with per-call crypto payments
- —On-demand AI inference (sentiment, summarization, classification, embeddings) without subscriptions
- —Fetching real-time financial data and crypto gas estimates
- —Geocoding and data validation as utility microservices
Fit
Best for
- —Developers and agents wanting zero-signup, pay-as-you-go API access
- —Crypto-native applications that can settle in USDC on Base
- —Low-volume or bursty workloads where subscription pricing is wasteful
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads requiring negotiated pricing or rate-limit guarantees
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/14 \
-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 schema, no request/response examples, and no documentation explaining what /api/v1/keys/14 actually returns. The crawled pages beyond the homepage were empty. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —The specific functionality of /api/v1/keys/14 ('Premium API Access') is undocumented — unclear what data or service it provides
- —Crawled docs, pricing, and README pages returned no useful content beyond 'Connect wallet'
- —No request or response examples available
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/keys/14
- —All listed endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/keys/14