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/7` 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; each request is paid for individually with an on-chain USDC transaction.
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 and instant access.
Note that the specific functionality behind `/api/v1/keys/7` ("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) all resolve to a minimal "Connect wallet" prompt with no additional detail. The endpoint is confirmed live via a valid 402 challenge, but what it actually returns upon successful payment is unknown.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API key management
- —On-demand API access where usage is sporadic and subscriptions are wasteful
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402-compatible agents that can settle USDC on Base automatically
- —Low-volume or bursty workloads where per-call pricing is economical
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/7 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation of what this specific endpoint does, no request/response schema, no OpenAPI spec, and the crawled pages beyond the landing page are empty. The listing is effectively a stub.
Warnings
- —No documentation exists for what /api/v1/keys/7 actually returns upon successful payment
- —No OpenAPI or request/response schema available
- —Crawled docs pages (/api, /pricing, /README) all returned only a 'Connect wallet' prompt with no content
- —The endpoint name 'Premium API Access' is generic and does not describe functionality
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/keys/7
- —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 across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/7