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 89) via the x402 payment protocol. It is one of many endpoints offered by the lowpaymentfee.com platform, which hosts a variety of pay-per-request APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services — all gated behind x402 micropayments settled in USDC on the Base network.
The specific endpoint `/api/v1/products/89/inventory` is labeled "Premium API Access" and accepts POST requests. The x402 challenge indicates a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per request (USDC uses 6 decimals). The platform advertises uniform $0.02/request pricing across all its endpoints, with no API keys, no rate limits, and no minimum commitments required. Payment is made inline via the X-PAYMENT header per the x402 protocol.
Documentation on the site is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what the inventory data actually contains or what fields the POST body expects. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is difficult to know what data is returned or what input parameters are accepted.
Capabilities
Use cases
- —Querying product inventory data for product ID 89 via a single micropayment
- —Integrating pay-per-request inventory checks into automated agent workflows
- —Accessing inventory information without API key registration
Fit
Best for
- —Agents or services that need on-demand inventory data with no subscription
- —x402-compatible clients that can settle USDC on Base
- —Developers exploring x402 micropayment-gated APIs
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —High-volume inventory queries where per-request pricing may add up
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/89/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, and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no documentation of request/response formats, and no examples. The docs pages are empty. The specific purpose of this 'products/89/inventory' endpoint is undocumented beyond the generic label 'Premium API Access'.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or request/response schema provided; input parameters and output format are unknown
- —The endpoint path references a specific product ID (89) but no explanation of what product this refers to
- —The generic title 'Premium API Access' does not describe the actual functionality
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/products/89/inventory
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/products/89/inventory