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/4`) behind an x402 paywall. When called without payment, it returns a 402 challenge requesting USDC on the Base network. The specific endpoint appears to serve invoice data in JSON format via HTTP POST.
The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance/crypto data feeds, and utility services. All endpoints are listed at $0.02 per request with no API keys, no rate limits, and no commitments required. However, the specific endpoint probed here (`/api/v1/stripe/invoices/4`) is labeled "Premium API Access" and its x402 challenge specifies a maxAmountRequired of 20,000 base units of USDC (6 decimals), which equals $0.02 — consistent with the site's advertised pricing.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema documentation, and no examples available. The endpoint is live and responds with a valid x402 challenge, but the actual behavior and response format of the invoice endpoint remain undocumented.
Capabilities
Use cases
- —Retrieving Stripe invoice data via a single paid API call
- —Programmatic access to invoice records without traditional API key management
- —Agent-driven invoice lookups settled in USDC on Base
Fit
Best for
- —Agents or services that need on-demand invoice data without subscription overhead
- —Developers experimenting with x402 payment-gated APIs
- —Use cases requiring keyless, pay-as-you-go API access
Not for
- —Production workloads requiring documented request/response schemas
- —Bulk invoice retrieval where per-call pricing is inefficient
- —Users who need fiat-only payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/stripe/invoices/4
# Returns 402 with x402 challenge; attach X-PAYMENT header with USDC payment proof to access.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no examples. The purpose of a 'Stripe invoices/4' endpoint is unclear without further context.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all return only 'Connect wallet'
- —No OpenAPI or schema definition found
- —The specific purpose and response format of /api/v1/stripe/invoices/4 is undocumented
- —The endpoint path references a hardcoded invoice ID (4), which may indicate a demo or placeholder resource
Citations
- —The endpoint returns a 402 challenge requesting 20,000 base units of USDC (asset 0x8335…) on Base networkhttps://lowpaymentfee.com/api/v1/stripe/invoices/4
- —The site advertises $0.02 per request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform lists APIs across data analytics, AI/ML, finance/crypto, and infrastructure categorieshttps://lowpaymentfee.com