x402-gated premium API access on Base, paid per-request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" behind an x402 paywall. The specific resource path (`/api/v1/stripe/invoices/87`) suggests it returns invoice or billing-related data, though the exact response payload is not documented. Payment is settled on the Base network using USDC (contract 0x8335…2913) via the x402 "exact" scheme.
The x402 challenge advertises a maxAmountRequired of 20,000 base units. Since USDC uses 6 decimals, this converts to $0.02 per request — consistent with the site-wide pricing of $0.02/request displayed on the provider's landing page. The provider emphasizes no API keys, no rate limits, and instant access; callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform offers a range of endpoints spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance/crypto data feeds, and utility services — all at the same $0.02/request price point. Documentation beyond the landing page is extremely sparse: the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. No OpenAPI spec, request/response schemas, or usage examples are available.
Capabilities
Use cases
- —Retrieving invoice or billing data behind a per-request paywall
- —Programmatic access to premium data without API key registration
- —Agent-driven workflows that need on-demand paid data retrieval
Fit
Best for
- —Agents or scripts that can settle x402 payments in USDC on Base
- —Use cases requiring keyless, pay-as-you-go API access
- —Low-volume callers who want no subscription commitment
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume batch processing where per-request fees add up quickly
- —Callers without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/stripe/invoices/87 \
-H "X-PAYMENT: <x402-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The specific purpose of the /stripe/invoices/87 path is undocumented. This is effectively a stub listing.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README all return only a wallet-connect prompt
- —No request or response schema provided; the exact data returned by this endpoint is unknown
- —The endpoint path references a specific invoice ID (87), which may indicate a demo or placeholder resource rather than a general-purpose API
- —No OpenAPI or ai-plugin manifest discovered
Citations
- —x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/stripe/invoices/87
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/stripe/invoices/87