x402-gated API suite on Base: analytics, AI, finance, and utility endpoints at $0.02/request via USDC.
What it does
lowpaymentfee.com is a collection of x402-protocol pay-per-call API endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/stripe/charges/140` is listed as "Premium API Access" and returns a standard x402 challenge requiring payment of up to 20,000 base units of USDC (0.02 USD) per request. The site advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform offers endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point.
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 spec, no request/response schema documentation, and no usage examples available from the crawl. The specific functionality behind the `/api/v1/stripe/charges/140` path is unclear; the name suggests it may relate to Stripe charge data, but this is not confirmed by any documentation. The endpoint is live and returns a well-formed x402 challenge.
Capabilities
Use cases
- —Paying per-call for API access without managing API keys or subscriptions
- —Programmatic agent access to gated endpoints using x402 USDC micropayments
- —Testing x402 protocol integration with a live endpoint on Base
Fit
Best for
- —Developers exploring x402 protocol pay-per-call patterns
- —AI agents that need keyless, on-demand API access settled in USDC
- —Projects wanting to avoid subscription commitments for low-volume API usage
Not for
- —Users needing well-documented API contracts with clear request/response schemas
- —High-volume production workloads where $0.02/request adds up significantly
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/stripe/charges/140 \
-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 spec, no request/response schema, no examples, and the actual functionality behind this specific endpoint path is unclear. The listing is effectively a stub.
Warnings
- —No documentation available — all doc pages render only 'Connect wallet'
- —No OpenAPI or schema definition found
- —The specific purpose of /api/v1/stripe/charges/140 is undocumented and unclear
- —No request body schema or response format documented anywhere
- —Cannot verify what data or service this endpoint actually provides
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/stripe/charges/140
- —All endpoints are priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/stripe/charges/140
- —Documentation pages (/docs, /api, /pricing, /README) show only 'Connect wallet'https://lowpaymentfee.com/docs