Pay-per-call API platform on Base network via x402 — $0.02/request in USDC, no API keys required.
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 `/api/v1/payments/261` is listed as "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals) per call. The platform 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 lowpaymentfee.com 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.
This particular endpoint (`/api/v1/payments/261`) is labeled generically as "Premium API Access" and does not appear in the site's public endpoint catalog, so its exact functionality is unclear. It accepts POST requests and returns `application/json`. The x402 challenge is live and well-formed, settling to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. Documentation pages beyond the landing page returned only a "Connect wallet" prompt with no substantive content.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without managing API keys or subscriptions
- —Agent-driven workflows that need to pay for API calls on-the-fly using USDC on Base
- —Testing x402 protocol integrations with a low-cost live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that need keyless, pay-as-you-go API access
- —Users who want to avoid subscription commitments for occasional API calls
Not for
- —Users needing detailed documentation or OpenAPI schemas before integrating
- —High-volume use cases where $0.02/request adds up significantly
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/261 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint works. However, the endpoint's actual functionality is unknown — it's labeled generically as 'Premium API Access' and doesn't match any cataloged endpoint. Documentation pages are empty (wallet-connect only), there's no OpenAPI spec, no request/response examples, and no description of what this specific endpoint returns.
Warnings
- —The endpoint /api/v1/payments/261 is not listed in the site's public API catalog; its actual functionality is unknown.
- —All documentation, pricing, API, and README pages return only a 'Connect wallet' prompt with no substantive content.
- —No OpenAPI schema, request format, or response examples are available.
- —The generic name 'Premium API Access' does not describe what the endpoint does.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/261
- —USDC contract address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/261
- —Platform advertises $0.02/request, no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —Platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com