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/111` 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 required; 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 $0.02 per request.
However, the specific endpoint probed (`/api/v1/transfers/111`) does not clearly map to any of the documented API categories on the landing page. Its description is simply "Premium API Access" with no further documentation about what data or functionality it returns. The docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no substantive content. Without documentation or example responses, the actual behavior of this endpoint remains unclear.
Capabilities
Use cases
- —Programmatic access to paid API endpoints without traditional API key management
- —Agent-driven workflows that need to pay per call using on-chain USDC
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that need keyless, pay-per-use API access
- —Low-cost per-request API consumption on Base L2
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume batch processing where per-request fees add up
- —Anyone needing clarity on what this specific endpoint actually returns
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transfers/111 \
-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 pricing and payment details. However, there is no documentation, no OpenAPI schema, no example requests or responses, and the specific endpoint path (/api/v1/transfers/111) is not described anywhere on the site. The docs/pricing/API pages all render only 'Connect wallet' with no content. The actual functionality of this endpoint is unknown.
Warnings
- —The endpoint /api/v1/transfers/111 is not listed among the documented APIs on the landing page — its purpose is unclear.
- —All documentation pages (docs, pricing, API, README) render only 'Connect wallet' with no substantive content.
- —No OpenAPI spec, no example request/response, and no description of what this endpoint returns.
- —The platform lists many API categories (AI, finance, analytics, etc.) but none are verifiable from the crawl data.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transfers/111
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transfers/111
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Landing page lists API categories including Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com