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 hosts a collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and general utility services. Every endpoint is priced at $0.02 per request, paid in USDC on the Base network via the x402 protocol. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/inbox/48` is listed as "Premium API Access" but its exact functionality is not documented beyond that label. The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation. All endpoints accept POST requests and return JSON.
The x402 challenge confirms the endpoint is live on Base, accepting USDC (contract 0x8335…2913) with a max amount of 20,000 base units (i.e., $0.02 given USDC's 6 decimals). Settlement goes to address 0x1A2B…85F3 with a 300-second timeout. No OpenAPI schema, detailed documentation, or example responses were found in the crawl.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification) without managing API keys
- —Fetching real-time crypto token quotes and gas estimates via micropayment
- —Geocoding or data validation as a utility service with no subscription commitment
- —Exporting analytics data or generating insights on a per-request basis
Fit
Best for
- —AI agents needing key-free, pay-per-call access to diverse utility endpoints
- —Developers prototyping with low-cost API calls on Base/USDC
- —Web3-native applications that prefer on-chain micropayments over traditional billing
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed SLAs, guaranteed uptime, or enterprise support
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/48 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but the specific endpoint /api/v1/inbox/48 has no documentation, no schema, no example request/response, and its purpose ('Premium API Access') is vague. The broader platform lists many endpoints but none have detailed docs. Effectively a stub listing.
Warnings
- —The exact functionality of /api/v1/inbox/48 ('Premium API Access') is undocumented — it is unclear what this endpoint actually does.
- —No OpenAPI schema, request/response examples, or detailed documentation found for any endpoint on the platform.
- —The /api, /pricing, and /README pages all returned only a 'Connect wallet' prompt with no useful content.
- —The platform lists many endpoint categories but none have been independently verified for actual functionality.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/inbox/48
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com