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/99` 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 with a signed USDC payment 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. The platform claims no rate limits, no minimums, and instant access.
Note that the specific functionality behind `/api/v1/keys/99` ("Premium API Access") is not documented beyond its title. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawled pages. The broader endpoint catalog gives context for the platform but the exact behavior of this particular route remains unclear.
Capabilities
Use cases
- —Agents that need on-demand access to AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time financial data (prices, exchange rates, gas estimates) with per-call USDC micropayments
- —Running utility operations like geocoding or data validation without subscription commitments
- —Programmatic data export and analytics reporting paid per request
Fit
Best for
- —AI agents or bots that need frictionless, keyless API access settled on-chain
- —Developers who want pay-as-you-go pricing with no minimums or rate limits
- —Web3-native applications that already hold USDC on Base
Not for
- —High-volume production workloads where $0.02/request adds up significantly compared to subscription-based alternatives
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/99 \
-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 documentation for what /api/v1/keys/99 actually returns, and the crawled pages beyond the homepage are empty wallet-connect stubs. The specific endpoint's purpose is essentially undocumented.
Warnings
- —No OpenAPI or schema available — request and response formats are unknown
- —The exact functionality of /api/v1/keys/99 ('Premium API Access') is not documented anywhere in the crawled material
- —Documentation, pricing, and README pages all returned only a 'Connect wallet' stub with no useful content
- —No rate limit or SLA information available despite the claim of 'no rate limits'
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x8335…) on Base networkhttps://lowpaymentfee.com/api/v1/keys/99
- —All listed endpoints cost $0.02 per request with no API keys, no rate limits, no minimumshttps://lowpaymentfee.com
- —Platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com