x402-gated Stripe invoice endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a Stripe invoice resource (`/api/v1/stripe/invoices/71`) behind an x402 paywall. When called without payment, it returns a 402 challenge requesting USDC on the Base network. The challenge specifies a maximum amount of 20,000 base units of USDC (0x8335…), which equals $0.02 USD (USDC uses 6 decimals). Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using the "exact" scheme with a 300-second timeout.
The hosting site lowpaymentfee.com advertises a broad catalog of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and no commitments. However, the specific endpoint in this listing (`/api/v1/stripe/invoices/71`) is labeled "Premium API Access" and appears to be a Stripe invoice resource rather than one of the general-purpose APIs listed on the homepage. Documentation pages (/docs, /api, /pricing, /README) returned only a "Connect wallet" prompt with no substantive content.
Because there is no OpenAPI schema, no request/response examples, and no documentation beyond the 402 challenge and the homepage listing, the actual behavior and output of this endpoint remain unclear. The endpoint is live and responds correctly with an x402 challenge, but prospective callers should be aware that the purpose and response format are not documented.
Capabilities
Use cases
- —Retrieving a Stripe invoice record via a crypto-paid API call
- —Programmatic access to invoice data without traditional API key management
- —Agent-driven payment and data retrieval in a single HTTP round-trip
Fit
Best for
- —Developers who want keyless, pay-per-request access to invoice data
- —AI agents that can settle x402 USDC payments on Base
- —Workflows needing one-shot invoice lookups without subscription overhead
Not for
- —Users needing documented request/response schemas before integration
- —Bulk invoice processing requiring rate-limited or batched access
- —Anyone without a USDC balance on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/stripe/invoices/71
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment to access.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no OpenAPI schema, no documentation, no request/response examples, and the purpose of the specific invoice resource is unclear. The docs, pricing, and README pages are all blank beyond a wallet-connect prompt.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —All documentation pages (/docs, /api, /pricing, /README) return only 'Connect wallet' with no content
- —The specific resource '/api/v1/stripe/invoices/71' is not listed among the homepage's advertised APIs — its purpose and response format are unknown
- —No example request or response bodies are available
Citations
- —The endpoint returns a 402 challenge requesting 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/stripe/invoices/71
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/stripe/invoices/71
- —The site advertises $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Documentation pages return only a 'Connect wallet' prompt with no substantive contenthttps://lowpaymentfee.com/docs