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 12) via 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 endpoint is part of a broader platform (lowpaymentfee.com) that offers a variety of x402-gated APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request. The platform advertises no API keys, no rate limits, and instant access; callers simply attach an x402 payment header to each request.
The specific functionality of this particular endpoint — product inventory lookup or management — is not well-documented. The crawled site pages (docs, pricing, README) all returned only a "Connect wallet" prompt with no additional technical documentation. There is no OpenAPI spec, no request/response schema, and no example payloads available. The endpoint is confirmed live (returns a proper 402 x402 challenge), but the lack of documentation means callers will need to experiment to discover the expected request body and response format.
Capabilities
Use cases
- —Querying product inventory data for product ID 12 via a single paid API call
- —Integrating pay-per-use inventory checks into an automated agent workflow
- —Demonstrating x402 protocol payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol integrations
- —Agents needing on-demand inventory data without API key registration
- —Low-volume, pay-as-you-go inventory queries
Not for
- —High-volume inventory management requiring bulk operations or subscriptions
- —Use cases requiring detailed API documentation or guaranteed SLAs
- —Users who need non-USDC or non-Base-network payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/12/inventory \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The endpoint's actual functionality (what it returns, what input it expects) is entirely undocumented.
Warnings
- —No API documentation available — docs, pricing, and README pages all return only a 'Connect wallet' prompt with no technical content.
- —No OpenAPI or JSON schema for request or response bodies; callers must discover the interface by experimentation.
- —The specific purpose of '/api/v1/products/12/inventory' is unclear — 'Premium API Access' is a generic label used across the platform.
- —No information on uptime, SLAs, or data freshness guarantees.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Base network.https://lowpaymentfee.com/api/v1/products/12/inventory
- —The platform prices all APIs at $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —USDC contract address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/products/12/inventory