Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API marketplace that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network using the x402 payment protocol. There are no API keys, no rate limits, and no subscription commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/item/5` is listed as "Premium API Access" and returns `application/json`. Its x402 challenge advertises a max amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and is discoverable. The broader platform also hosts endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The exact functionality behind `/api/v1/item/5` ("Premium API Access") is unclear and cannot be determined from available materials.
Capabilities
Use cases
- —Accessing premium API data without managing API keys or subscriptions
- —Making one-off paid API calls settled in USDC on Base
- —Agent-driven workflows that need instant, keyless API access with crypto payment
Fit
Best for
- —Developers who want pay-as-you-go API access without signup
- —AI agents that can attach x402 payment headers automatically
- —Users with USDC on Base looking for low-cost API calls
Not for
- —Users who need detailed API documentation or schemas before integrating
- —High-volume consumers who want bulk pricing or subscription discounts
- —Developers without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/item/5 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it works. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no description of what '/api/v1/item/5' actually returns. The listing is effectively a stub with confirmed liveness and pricing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README pages all render only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The exact functionality of /api/v1/item/5 ('Premium API Access') is unknown — the name is generic and no further details are available
- —Cannot verify what data or service is actually returned by this endpoint
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 (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/item/5
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs