Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, 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/transfers/107` is listed as "Premium API Access" and costs $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, accounts, or rate limits are advertised — callers simply attach an X-PAYMENT header with a valid x402 payment proof to access the resource.
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 endpoint probed here (`/api/v1/transfers/107`) does not clearly map to any of the advertised API categories on the landing page. The "transfers" path and "Premium API Access" label are not documented elsewhere on the site. The docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive documentation. Without documentation or schema details for this endpoint, it is unclear what data or functionality it actually provides when a valid payment is submitted.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API keys or subscriptions
- —Agent-driven workflows that settle per-request costs in USDC on Base
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers exploring x402 payment protocol integrations
- —Agents needing keyless, pay-as-you-go API access
- —Low-volume callers who want no subscription commitment
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume use cases where $0.02/request adds up significantly
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transfers/107 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge), but there is no documentation, no request/response schema, and the specific endpoint path does not match any advertised API on the landing page. Docs pages return only 'Connect wallet' with no content. The actual functionality behind this endpoint is unknown.
Warnings
- —The endpoint path /api/v1/transfers/107 is not listed among the advertised APIs on the landing page — its actual functionality is unclear.
- —All documentation pages (docs, API, pricing, README) returned only 'Connect wallet' with no substantive content.
- —No request body schema or response schema is available — callers cannot know what to send or what to expect back.
- —No OpenAPI spec, ai-plugin manifest, or agents.txt was found.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transfers/107
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transfers/107
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Multiple API categories listed including Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com