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 56) via the x402 payment protocol. It is part of a broader platform that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services — all gated behind x402 challenges on the Base network using USDC.
The specific endpoint `/api/v1/products/56/inventory` is listed as "Premium API Access" and accepts POST requests. Payment is settled on-chain on Base using USDC (contract 0x8335…2913) with a maximum amount of 20,000 base units, which equals $0.02 (USDC uses 6 decimals). The platform advertises a flat $0.02 per request across all its endpoints, with no API keys, no rate limits, and instant access.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further 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 x402 challenge), but without documentation it is unclear what payload to send or what response structure to expect.
Capabilities
Use cases
- —Querying product inventory data for product ID 56 via a single paid API call
- —Integrating pay-per-request inventory checks into an agent workflow without managing API keys
- —Demonstrating x402 protocol usage for on-chain micropayments on Base
Fit
Best for
- —Developers experimenting with x402 payment protocol integrations
- —Agents that need keyless, pay-per-call access to inventory data
- —Projects already using USDC on Base that want frictionless API access
Not for
- —Production inventory management requiring documented schemas and SLAs
- —Users who need detailed API documentation or request/response examples before integrating
- —High-volume use cases where $0.02 per request adds up without bulk pricing
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/56/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 documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and no description of what data the inventory endpoint actually returns. The listing is effectively a stub.
Warnings
- —No API documentation available — all doc pages render only 'Connect wallet'
- —No OpenAPI or JSON schema describing request body or response format
- —Purpose of 'Premium API Access' / product 56 inventory is undocumented
- —No request or response examples available anywhere in crawled content
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/products/56/inventory
- —Platform advertises $0.02 per request, no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/products/56/inventory