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/130` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys or accounts are required — callers authenticate and pay via the x402 payment header protocol.
The 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. The site claims no rate limits and instant access.
However, the specific `/api/v1/inbox/130` endpoint's purpose is unclear — it does not match any of the named endpoints on the landing page, and the description "Premium API Access" is generic. There is no OpenAPI schema, no request/response documentation, and the crawled /api, /pricing, and /README pages returned only a "Connect wallet" prompt with no useful content. Without documentation or examples, it is difficult to determine what this particular endpoint actually does or what request body it expects.
Capabilities
Use cases
- —Programmatic access to pay-per-call API services without managing API keys or subscriptions
- —Agent-driven workflows that need on-demand API calls settled in USDC on Base
- —Exploring x402 payment protocol integration with various utility and data endpoints
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402 protocol experimentation on Base with low per-call costs
- —Scenarios where avoiding API key management is a priority
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads where $0.02/request adds up without volume discounts
- —Anyone needing non-USDC or non-Base payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/130 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (returns a valid 402 x402 challenge) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no request/response examples, and the specific endpoint path '/api/v1/inbox/130' does not correspond to any named service on the landing page. The purpose of this particular endpoint is unknown.
Warnings
- —The endpoint path /api/v1/inbox/130 does not match any documented API on the landing page — its actual function is unknown.
- —No OpenAPI schema, request format, or response format documentation is available.
- —The /api, /pricing, and /README pages returned no useful content beyond 'Connect wallet'.
- —The generic description 'Premium API Access' provides no insight into what the endpoint does.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/130
- —All listed endpoints are priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/inbox/130