Pay-per-request product inventory API on Base via x402, settled in USDC at $0.02/call.
What it does
This endpoint at lowpaymentfee.com provides access to product inventory data (specifically product ID 5) behind an x402 paywall. It uses the exact payment scheme on the Base network, accepting USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) at a cost of $0.02 per request (20,000 base units with 6 decimals). No API keys or rate limits are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The endpoint is part of a broader suite of APIs offered by lowpaymentfee.com, which spans data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced uniformly at $0.02 per request. The specific endpoint listed here serves inventory data and responds with application/json. It is accessed via HTTP GET and is marked as discoverable in the output schema.
Documentation on the site 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 example request/response payloads, and no detailed description of what the inventory response contains. The x402 challenge was successfully captured (HTTP 402), confirming the endpoint is live.
Capabilities
Use cases
- —Querying real-time product inventory levels without needing an API key
- —Integrating inventory checks into autonomous agent workflows that can settle payments on Base
- —Building e-commerce or supply-chain tools that pay per data request
Fit
Best for
- —Agents or bots that need frictionless, keyless API access to inventory data
- —Developers experimenting with x402 payment-gated APIs on Base
- —Low-volume or sporadic inventory lookups where $0.02/call is cost-effective
Not for
- —High-volume inventory polling where per-request fees would accumulate quickly
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X GET https://lowpaymentfee.com/api/v1/products/5/inventory \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no example responses, and all documentation pages are empty stubs. The actual content of the inventory response is unknown, making this effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — response format is unknown
- —All doc/pricing/README pages render only 'Connect wallet' with no useful content
- —The specific data returned by the /products/5/inventory endpoint is undocumented
- —No example request or response payloads could be sourced
Citations
- —Endpoint returns HTTP 402 with x402 challenge, confirming it is livehttps://lowpaymentfee.com/api/v1/products/5/inventory
- —Price is 20,000 base units of USDC (6 decimals) = $0.02 per request on Base networkhttps://lowpaymentfee.com/api/v1/products/5/inventory
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/products/5/inventory
- —All APIs on the site are priced at $0.02/request with no API keys or rate limitshttps://lowpaymentfee.com