x402-gated product inventory endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a "Premium API Access" resource at the path `/api/v1/products/13/inventory`. It is part of a broader platform (lowpaymentfee.com) that offers dozens of x402-payable API endpoints spanning data analytics, AI/ML inference, finance, crypto, and utility services — all settled on the Base network using USDC.
The specific endpoint returns product inventory data (product ID 13) via HTTP POST. Payment is handled through the x402 protocol: callers receive a 402 challenge containing the payment terms, construct an on-chain USDC micro-payment on Base, and attach the payment proof in an `X-PAYMENT` header. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 USD. The platform advertises no API keys, no rate limits, and instant access.
Documentation on the site is extremely thin — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawl. The endpoint is confirmed live (returns a proper 402 challenge), but the actual response payload structure for a successful paid request is unknown.
Capabilities
Use cases
- —Querying real-time product inventory data for product ID 13 via a single micro-payment
- —Integrating pay-per-call inventory checks into an autonomous agent workflow
- —Demonstrating x402 protocol usage for commerce data retrieval
Fit
Best for
- —Agents or services needing on-demand inventory lookups without subscription commitments
- —Developers experimenting with x402 micro-payment protocol on Base
- —Low-volume, pay-as-you-go product data consumers
Not for
- —High-volume inventory monitoring requiring bulk or subscription pricing
- —Users who need detailed API documentation or response schema guarantees before integrating
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/13/inventory
# Returns 402 with x402 challenge. Attach X-PAYMENT header with signed USDC payment proof on Base to complete the request.Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request body schema, no response schema, no documentation beyond a wallet-connect prompt, and no examples. The purpose ('Premium API Access' for product 13 inventory) is vague and unverifiable. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages all render only 'Connect wallet'
- —No OpenAPI or request/response schema provided; actual payload structure is unknown
- —The endpoint name 'Premium API Access' and path '/products/13/inventory' give minimal context about what data is actually returned
- —Cannot verify what inventory data is served without making a paid request
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/products/13/inventory
- —The platform advertises $0.02 per request, no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/products/13/inventory