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 `/api/v1/transfers/103` is listed as "Premium API Access" and returns a 402 challenge requiring payment of up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys 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 including 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 of the `/api/v1/transfers/103` endpoint is unclear. The description simply says "Premium API Access" with no further documentation about what data or service it returns. The docs, pricing, and API pages on the site all render only a "Connect wallet" prompt with no additional technical documentation, OpenAPI schema, or usage examples. Prospective users should be aware that the actual response payload and input parameters for this endpoint are undocumented.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API key registration
- —Agent-driven workflows that settle per-request costs in USDC on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents with x402-compatible wallets on Base
- —Prototyping x402 payment integrations
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —Anyone without a Base-network USDC wallet
- —High-volume use cases where per-request pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transfers/103 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no documentation, no OpenAPI schema, no example request/response, and the actual functionality behind 'Premium API Access' at /api/v1/transfers/103 is completely undocumented. All doc pages render only 'Connect wallet' with no content.
Warnings
- —The specific functionality of /api/v1/transfers/103 is undocumented — 'Premium API Access' is the only description available.
- —No OpenAPI schema, request parameters, or response format documentation exists.
- —All documentation pages (docs, pricing, API, README) render only a 'Connect wallet' prompt with no technical content.
- —The platform lists many API categories but it is unclear which are actually functional versus placeholder.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transfers/103
- —All endpoints are priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform advertises Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transfers/103