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/93` 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 simply attach an X-PAYMENT header with a valid payment proof.
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 endpoints are listed at the same $0.02 per request price point.
However, the specific functionality behind the `/api/v1/keys/93` endpoint is unclear. The description simply says "Premium API Access" with no further documentation, input/output schema, or examples. The crawled docs pages (/api, /pricing, /README) all returned only a "Connect wallet" prompt with no substantive content. Without documentation or schema details, it is difficult to know what this particular endpoint returns or what input it expects beyond a POST request.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing an account or API key
- —Agent-driven workflows that need on-demand API access with crypto micropayments
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers exploring x402 pay-per-call patterns
- —AI agents that need frictionless API access without pre-registration
- —Users who want to pay per request in USDC on Base
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone requiring non-crypto payment methods
- —High-volume use cases where per-request pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/93 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no input/output schema, no examples, and the purpose of this specific endpoint (/api/v1/keys/93) is entirely opaque. The crawled doc pages were empty beyond a wallet-connect prompt.
Warnings
- —No documentation available for this specific endpoint — purpose of /api/v1/keys/93 is unknown
- —No input or output schema provided; callers cannot know what to send or expect back
- —All documentation pages (/api, /pricing, /README) returned only 'Connect wallet' with no content
- —The endpoint name 'Premium API Access' is generic and does not describe functionality
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/93
- —All endpoints are listed 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 address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/keys/93