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 3) via the x402 payment protocol. The endpoint is live and returns a 402 challenge requiring payment in USDC on the Base network. The cost per request is $0.02 (20,000 base units of USDC with 6 decimals). Payment is made via the x402 "exact" scheme — a single per-call micropayment settled on-chain.
The hosting site lowpaymentfee.com offers a broad catalog of x402-gated APIs spanning data & analytics, AI/ML inference (sentiment, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request with no API keys, no rate limits, and instant access.
This specific endpoint (`/api/v1/products/3/inventory`) is labeled "Premium API Access" in the x402 challenge description. No further documentation, request/response schema, or examples are provided by the site — the docs, pricing, and API pages all render only a wallet-connect prompt with no additional content. The exact nature of the "inventory" data returned is unclear from available material.
Capabilities
Use cases
- —Querying product inventory data with per-request USDC micropayments
- —Integrating x402 payment-gated data into agent workflows
- —Accessing inventory information without API keys or subscriptions
Fit
Best for
- —Agents or apps that can settle x402 payments on Base
- —Developers wanting keyless, pay-per-use API access
- —Micropayment-native workflows needing inventory data
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —Applications requiring free or subscription-based access without on-chain payments
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/3/inventory \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no documentation, no request/response schema, and no examples. The purpose of the 'inventory' resource is unclear. Docs pages render only a wallet-connect prompt with no content.
Warnings
- —No request or response schema available — the exact data returned by this endpoint is unknown.
- —Documentation pages (/docs, /api, /pricing, /README) all render only a wallet-connect prompt with no useful content.
- —The label 'Premium API Access' is generic and does not describe what the endpoint actually returns.
- —Cannot verify what 'products/3/inventory' contains without making a paid request.
Citations
- —Endpoint returns HTTP 402 with x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/products/3/inventory
- —maxAmountRequired is 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913), equaling $0.02https://lowpaymentfee.com/api/v1/products/3/inventory
- —Site lists all APIs at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Site offers APIs across data/analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com