Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/inbox/104` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — no API keys, accounts, or subscriptions are required; callers simply attach an X-PAYMENT header with a valid payment proof.
The wider platform advertises four endpoint 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.
Important caveat: the specific `/api/v1/inbox/104` endpoint does not clearly map to any of the named API categories on the landing page. Its purpose is described only as "Premium API Access" with no further documentation, input schema, or example responses available. The platform's /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no additional content. Without documentation or response examples, the actual functionality behind this endpoint remains unclear.
Capabilities
Use cases
- —Accessing pay-per-request API services without needing an API key or subscription
- —Making micropayment-settled API calls using USDC on Base
- —Agent-driven API consumption where payment is embedded in the request header
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over traditional billing
Not for
- —Users needing detailed API documentation or guaranteed SLAs before purchasing
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/104 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge), but there is no documentation, no input/output schema, no example responses, and the endpoint path (/api/v1/inbox/104) does not correspond to any documented API on the landing page. The /api, /pricing, and /README pages are all empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —The endpoint path /api/v1/inbox/104 does not match any of the documented API routes on the landing page — its actual functionality is unknown.
- —No input schema, output schema, or example responses are available for this endpoint.
- —All documentation pages (/api, /pricing, /README) returned only a 'Connect wallet' prompt with no useful content.
- —The platform's broader API catalog (AI, data, finance, utils) is advertised but none of those endpoints were probed — only /api/v1/inbox/104 was confirmed live.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/104
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/inbox/104