x402-gated product inventory endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a product inventory resource (product ID 18) behind an x402 paywall. The endpoint accepts POST requests and returns JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) via the x402 "exact" scheme. The maximum amount required per call is 20,000 base units of USDC, which equals $0.02 (USDC uses 6 decimals).
The hosting site lowpaymentfee.com offers a broad catalog of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and no commitments. However, the specific endpoint listed here (/api/v1/products/18/inventory) is labeled "Premium API Access" and does not appear in the site's main catalog of advertised APIs. Its exact response payload and business logic are undocumented; the only confirmed details come from the x402 challenge itself.
The endpoint is live: it returns a well-formed x402 version 1 challenge with a 402 status code. No OpenAPI schema, detailed documentation, or example responses were found in the crawl. The docs, API, pricing, and README pages all rendered only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Querying product inventory data for product ID 18 via a single paid API call
- —Integrating pay-per-request inventory lookups into an agent workflow
- —Demonstrating x402 payment protocol integration on Base
Fit
Best for
- —Agents or developers needing on-demand inventory data without API key management
- —x402 protocol experimentation and integration testing
- —Micropayment-gated data access on Base
Not for
- —Bulk or high-frequency inventory queries where per-call pricing is inefficient
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/18/inventory \
-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 OpenAPI schema, no documentation of request/response payloads, and the specific endpoint is not listed in the site's own catalog. The crawled docs/pricing/API pages were empty beyond a wallet prompt. Almost everything is inferred from the 402 challenge alone.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —This specific endpoint (/api/v1/products/18/inventory) does not appear in the provider's advertised API catalog
- —Docs, pricing, and API pages returned only 'Connect wallet' with no substantive content
- —Response format and fields are completely unknown — no example responses available
- —The description 'Premium API Access' is generic and does not clarify what data is returned
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/products/18/inventory
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/products/18/inventory
- —Site advertises $0.02 per request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —The site lists APIs across data/analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com