Pay-per-request API suite on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints across four 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 priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no minimum commitments.
The specific endpoint at `/api/v1/products/45` is labeled "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is via the x402 exact scheme, with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
Documentation beyond the landing page is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no additional technical content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available. The actual behavior of the `/api/v1/products/45` endpoint (what data it returns, what input it expects) is not documented anywhere in the crawled material.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting data with instant, keyless access
- —Using utility services like geocoding, validation, and conversion via micropayments
Fit
Best for
- —Agents or applications that need low-friction, keyless API access paid per request
- —Developers who want to avoid subscription commitments for occasional API calls
- —Web3-native workflows that can settle payments in USDC on Base
Not for
- —High-volume production workloads where per-request pricing at $0.02 adds up quickly
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/45 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, documentation is essentially nonexistent — all doc/pricing/readme pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no examples. The purpose of /api/v1/products/45 specifically is undocumented. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or schema documentation available
- —All documentation pages (/docs, /pricing, /README, /api) render only 'Connect wallet' with no content
- —The specific purpose and expected input/output of /api/v1/products/45 ('Premium API Access') is not documented anywhere
- —No request or response examples available — actual endpoint behavior is unknown
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with a 300-second timeouthttps://lowpaymentfee.com/api/v1/products/45
- —Categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Documentation pages /docs, /pricing, /api, /README all show only 'Connect wallet'https://lowpaymentfee.com/docs