x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request via USDC.
What it does
lowpaymentfee.com is an x402 protocol-based API marketplace that provides pay-per-request access to a variety of endpoints spanning data analytics, AI/ML inference, finance/crypto data, and utility services. All endpoints are gated behind x402 payment challenges settled in USDC on the Base network, with a uniform price of $0.02 per request (20,000 base units of USDC with 6 decimals).
The specific endpoint at `/api/v1/stripe/invoices/167` is labeled "Premium API Access" and accepts POST requests. It uses the exact payment scheme on Base, paying to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913). The maximum amount required is 20,000 base units ($0.02). The timeout for payment is 300 seconds.
The platform advertises no API keys, no rate limits, and instant access. Documentation pages exist but appear to require wallet connection to view content, so detailed request/response schemas are not available from the crawl. The broader site lists categories including metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation endpoints.
Capabilities
Use cases
- —Accessing premium API data without traditional API key registration
- —Making one-off paid API calls settled instantly via USDC on Base
- —Integrating pay-per-request services into autonomous agent workflows
- —Programmatic invoice or payment-related data retrieval
Fit
Best for
- —Developers wanting keyless, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users without USDC on Base network
- —Applications requiring detailed OpenAPI documentation before integration
- —High-volume use cases where subscription pricing would be more economical
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/stripe/invoices/167 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing and network details. However, there is no OpenAPI schema, no documented request/response format, and documentation pages are inaccessible without wallet connection. The purpose of the specific 'stripe/invoices/167' endpoint is unclear beyond its generic 'Premium API Access' label.
Warnings
- —No OpenAPI or request/response schema available
- —Documentation pages require wallet connection and provide no readable content
- —The specific purpose of /api/v1/stripe/invoices/167 is unclear - it may be a demo or placeholder endpoint
- —No information on what data is returned by this endpoint
Citations
- —Uniform pricing of $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units USDC on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/stripe/invoices/167
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/stripe/invoices/167