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 at `/api/v1/keys/71` 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 a 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 confirms the endpoint is live, accepts POST requests, and settles via the "exact" payment scheme on Base using USDC (contract 0x8335…2913).
Note that the specific functionality behind the `/api/v1/keys/71` path is not documented beyond the label "Premium API Access." There is no OpenAPI schema, no request/response examples, and the crawled docs pages (pricing, README, API) all resolve to a minimal "Connect wallet" page. Prospective callers should be aware that the actual behavior of this particular endpoint is unclear from available documentation.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Integrating low-cost data, AI, or utility endpoints without subscription commitments
Fit
Best for
- —Developers who want zero-signup, pay-per-call API access
- —AI agents with x402-compatible wallets on Base
- —Projects needing low-cost micropayment-settled API calls
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who prefer subscription-based pricing
- —Callers who cannot settle payments in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/71 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is no OpenAPI schema, no request/response examples, and no documentation explaining what this specific endpoint actually does. The crawled pages beyond the homepage are empty. The endpoint's purpose is essentially unknown beyond its label.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —The specific functionality of /api/v1/keys/71 ('Premium API Access') is undocumented
- —Docs, pricing, and README pages all resolve to a minimal 'Connect wallet' stub with no content
- —Cannot verify what data or service this endpoint returns without making a paid request
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/71
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/71