Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/invoices/5` is listed as "Premium API Access" and its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base), which equals $0.02. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
The broader platform advertises additional endpoint categories including sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 per call price point. However, documentation beyond the landing page is essentially empty (all doc/pricing/API pages just show a "Connect wallet" prompt), so the actual behavior and response schemas of these endpoints are unknown.
Capabilities
Use cases
- —Accessing premium API data without creating an account or managing API keys
- —Making one-off paid API calls settled instantly in USDC on Base
- —Programmatic invoice retrieval via pay-per-request model
Fit
Best for
- —Developers who want zero-signup, pay-as-you-go API access
- —Agents and bots that can attach x402 payment headers automatically
- —Users already holding USDC on the Base network
Not for
- —Users who need detailed API documentation or response schema guarantees before paying
- —High-volume consumers who need bulk pricing or subscription discounts
- —Developers not set up for crypto payments on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/invoices/5 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no OpenAPI schema, no example requests or responses, and the purpose of the /api/v1/invoices/5 endpoint specifically is unclear. All documentation pages return only 'Connect wallet' with no content.
Warnings
- —No API documentation available — all doc pages render only a 'Connect wallet' prompt with no actual content.
- —The specific purpose and response format of /api/v1/invoices/5 is unknown; 'Premium API Access' is a generic label.
- —No OpenAPI spec, no output schema, and no example responses are provided anywhere.
- —The platform lists many endpoint categories (AI, finance, utilities) but none have documented schemas or verifiable functionality.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, scheme exact, 300s timeouthttps://lowpaymentfee.com/api/v1/invoices/5
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation, pricing, API, and README pages all render only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs