Pay-per-request API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/call.
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 at `/api/v1/keys/50` is listed as "Premium API Access" and costs up to $0.02 per request (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 per-request pricing. The x402 challenge was successfully captured with version 1 of the protocol, confirming the endpoint is live.
Note that the specific functionality behind the `/api/v1/keys/50` path is unclear — the description simply says "Premium API Access" without detailing what data or service it returns. No OpenAPI schema, request/response examples, or detailed documentation were found during the crawl. The /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without subscription
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates per request
- —Running utility operations like geocoding, validation, or data conversion with no upfront commitment
- —Accessing analytics metrics and reports with per-call billing
Fit
Best for
- —AI agents that need low-cost, no-auth API access settled on-chain
- —Developers prototyping with pay-as-you-go endpoints on Base
- —Applications requiring diverse lightweight API calls without managing API keys
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed SLAs, documentation, or guaranteed uptime
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/50 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"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 beyond a landing page listing endpoint names. The specific purpose of /api/v1/keys/50 is undocumented. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific functionality of /api/v1/keys/50 ('Premium API Access') is not described anywhere
- —All documentation pages (/api, /pricing, /README) returned only 'Connect wallet' with no content
- —No request or response examples are available to verify what the endpoint actually returns
- —The breadth of advertised capabilities (AI, finance, data, utilities) cannot be verified from available material
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/keys/50
- —All listed endpoints are priced at $0.02 per request with no API keys, rate limits, or commitmentshttps://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/50