x402-gated product inventory endpoint on Base, pay-per-request with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a product inventory resource (product ID 47) via the x402 payment protocol. It is part of a broader platform offering dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance, crypto, infrastructure utilities, and more — all gated behind x402 micropayments on the Base network using USDC.
The specific endpoint `/api/v1/products/47/inventory` is listed as "Premium API Access" and accepts POST requests. Payment is settled on-chain on Base using USDC (contract 0x8335…2913) with a maximum amount of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals). The platform advertises no API keys, no rate limits, and instant access — you simply attach an x402 payment header to each call.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what the inventory response actually contains. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is unclear what fields the POST body should contain or what the response payload looks like.
Capabilities
Use cases
- —Querying inventory status for a specific product via micropayment
- —Integrating pay-per-call inventory checks into an agent workflow
- —Accessing product data without API key registration
Fit
Best for
- —Agents that can settle x402 payments on Base with USDC
- —Quick one-off inventory lookups without subscription commitments
- —Developers exploring x402 protocol integrations
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume inventory queries where per-call pricing may add up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/47/inventory \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming it works. However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only a wallet-connect prompt. The actual purpose of the 'Premium API Access' / product inventory endpoint is unclear beyond its URL path. This is effectively a stub listing.
Warnings
- —No documentation available — all doc pages render only 'Connect wallet' with no content
- —No OpenAPI or schema describing request body or response format
- —The endpoint is labeled 'Premium API Access' which is generic and uninformative about what data it actually returns
- —Cannot confirm what POST body fields are expected or what the inventory response contains
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/products/47/inventory
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/products/47/inventory