Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint at /api/v1/payments/374 is labeled "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys, subscriptions, or rate limits are advertised — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API 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. However, the specific functionality behind the /api/v1/payments/374 endpoint is not documented beyond its "Premium API Access" label, and no request/response schemas are provided for any endpoint.
The endpoint is live and returns a proper 402 challenge. Payment settles in USDC (contract 0x8335…2913) on Base to address 0x1A2B…85F3 with a 300-second timeout. Documentation pages (/docs, /pricing, /api, /README) all render only a "Connect wallet" prompt with no substantive content, so the actual input parameters and response format for this endpoint remain unknown.
Capabilities
Use cases
- —Programmatic access to a generic pay-per-call API without needing API keys or subscriptions
- —Agent-driven workflows that settle per-request costs in USDC on Base
- —Testing x402 payment flows against a low-cost live endpoint
Fit
Best for
- —Developers exploring x402 protocol integration
- —Agents that need key-free, pay-as-you-go API access
- —Low-cost per-request experimentation on Base network
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Production workloads requiring well-documented request/response schemas
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/374 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is zero documentation on what this specific endpoint does, what inputs it accepts, or what it returns. All doc pages render only 'Connect wallet' with no content. The 'Premium API Access' label is generic and uninformative.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only a 'Connect wallet' prompt with no substantive content.
- —The specific functionality of /api/v1/payments/374 ('Premium API Access') is completely undocumented; it is unclear what this endpoint actually does.
- —No request or response schema is provided for any endpoint on the platform.
- —The platform lists many API categories (AI, finance, data, etc.) but none have visible documentation to verify actual functionality.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/374
- —All endpoints are listed at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/374
- —Documentation pages render only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs