x402-gated product inventory endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a product inventory resource at `/api/v1/products/39/inventory`, gated behind the x402 payment protocol. It accepts POST requests and returns JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) with a maximum cost of 0.02 USDC per request (20,000 base units at 6 decimals).
The parent site lowpaymentfee.com hosts a broad catalog of x402-gated APIs spanning data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and no minimum commitments. However, this specific endpoint (`/products/39/inventory`) is not listed on the site's landing page among the advertised API categories, so its exact response payload and business logic are unclear. The listing title "Premium API Access" and the path suggest it returns inventory data for a specific product (ID 39), but no documentation, schema, or example responses are available.
The endpoint is confirmed live: the probe received a well-formed HTTP 402 challenge with x402 version 1 headers. The output schema indicates it is discoverable and accepts HTTP POST. No OpenAPI spec, ai-plugin manifest, or detailed docs were found — the docs, pricing, API, and README pages all returned only a "Connect wallet" prompt with no substantive content.
Capabilities
Use cases
- —Querying inventory status for a specific product via a micropayment-gated API
- —Integrating pay-per-call product data into an agent workflow without API key management
- —Demonstrating x402 protocol payment flows on Base network
Fit
Best for
- —Agents or services that need on-demand product inventory checks without subscription commitments
- —Developers experimenting with x402 payment protocol integrations
- —Workflows requiring keyless, pay-as-you-go API access on Base
Not for
- —Users needing well-documented APIs with full OpenAPI specs and example responses
- —High-volume inventory polling where per-request fees would accumulate significantly
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/39/inventory \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but there is no documentation, no OpenAPI schema, no example requests or responses, and the specific endpoint is not even listed among the site's advertised APIs. The actual functionality behind 'products/39/inventory' is entirely opaque.
Warnings
- —No OpenAPI spec or schema available for this endpoint
- —No documentation beyond a 'Connect wallet' prompt on docs/pricing/API pages
- —This specific endpoint (/api/v1/products/39/inventory) is not listed among the site's advertised APIs — its purpose and response format are unknown
- —Response payload structure is completely undocumented
Citations
- —The endpoint returns HTTP 402 with x402 version 1 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/products/39/inventory
- —maxAmountRequired is 20000 base units of USDC (0.02 USDC) with asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/products/39/inventory
- —Site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Docs, pricing, API, and README pages return only a 'Connect wallet' prompt with no substantive documentationhttps://lowpaymentfee.com/docs