x402-gated product inventory endpoint on Base, paid per-request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a product inventory resource (product ID 11) behind an x402 paywall. The provider operates a broad catalog of pay-per-call APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services, all settled on the Base network using USDC.
The specific endpoint `/api/v1/products/11/inventory` accepts POST requests and returns JSON. Payment is handled via the x402 protocol: callers receive a 402 challenge with payment parameters, settle in USDC on Base, and include 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 provider advertises a flat $0.02/request price across all endpoints, no API keys, no rate limits, and instant access.
Documentation is extremely sparse — the docs, pricing, API, 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. The endpoint is live (returns a valid x402 challenge), but the lack of documentation makes it difficult to know what fields to send or what shape the response takes.
Capabilities
Use cases
- —Querying product inventory levels programmatically with per-request USDC payment
- —Integrating inventory checks into agent workflows without API key provisioning
- —Building commerce automation that pays per call on Base L2
Fit
Best for
- —Agents or bots that need on-demand inventory data without subscription commitments
- —Developers experimenting with x402 payment-gated APIs
- —Crypto-native applications already operating on Base
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —High-volume inventory polling where $0.02/request adds up quickly
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/11/inventory \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation is essentially nonexistent — every doc page shows only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and no description of what 'Premium API Access' for product 11 inventory actually returns. The listing is effectively a stub.
Warnings
- —No documentation available — all doc pages render only 'Connect wallet'
- —No OpenAPI or input/output schema provided; request body format is unknown
- —The specific data returned by this inventory endpoint is undocumented
- —Provider hosts many endpoints but none appear to have public documentation
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/products/11/inventory
- —The provider advertises $0.02/request flat pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/products/11/inventory