Pay-per-call API platform on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/invoices/17` is labeled "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). The platform advertises no API keys, no rate limits, and instant access — callers simply attach an x402 payment header to each request.
The site lists 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.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The invoices/17 endpoint specifically lacks any description beyond its title, so its exact functionality is unclear. Callers should expect to experiment or contact the provider for details on request and response formats.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting data with no subscription commitment
- —Using utility services like geocoding, validation, and conversion via micropayments
Fit
Best for
- —Agents or developers who want keyless, pay-as-you-go API access
- —Low-volume or bursty workloads where subscriptions are wasteful
- —Crypto-native applications already operating on the Base network
Not for
- —High-volume production workloads needing SLAs and guaranteed uptime (no documentation on reliability)
- —Users who need detailed API documentation or schema contracts before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/invoices/17 \
-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 spec, no request/response schema, no documentation beyond a wallet-connect prompt, and the specific purpose of /api/v1/invoices/17 is unexplained. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or schema documentation available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The specific endpoint /api/v1/invoices/17 has no description of what it returns or what input it expects
- —No examples of request or response payloads found in crawl material
- —The endpoint path 'invoices/17' suggests a specific resource rather than a general-purpose API — purpose is unclear
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/invoices/17
- —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 address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/invoices/17