Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no commitments required. The specific endpoint at `/api/v1/transactions/305` is labeled "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0.02 USD) on Base.
The platform advertises four broad categories of APIs: 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 (geocoding, validation, conversion, generation). All are listed at $0.02 per request. The x402 challenge confirms the endpoint is live, uses the "exact" payment scheme, and accepts USDC at contract address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what the `/api/v1/transactions/305` endpoint actually returns. The endpoint's purpose beyond the generic "Premium API Access" label is unclear.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching financial data like price feeds, exchange rates, and gas estimates on a per-call basis
- —Running data analytics queries and exporting data with micropayments
- —Using utility services like geocoding, validation, and conversion via x402
Fit
Best for
- —Agents or developers wanting zero-signup, pay-per-use API access
- —Crypto-native workflows that can settle USDC on Base
- —Low-volume or sporadic API usage where subscriptions are wasteful
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —High-volume production workloads requiring predictable bulk pricing
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/305 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is zero documentation on what this specific endpoint does, no request/response schemas, and all doc pages render only 'Connect wallet'. The endpoint label 'Premium API Access' is generic and uninformative. Effectively a stub listing.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README all show only 'Connect wallet'
- —No OpenAPI spec or request/response schema provided
- —The specific purpose of /api/v1/transactions/305 ('Premium API Access') is unclear and undocumented
- —Cannot verify what data or functionality this endpoint actually returns
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 x402 challenge for /api/v1/transactions/305 requests maxAmountRequired of 20000 base units of USDC (USD Coin) on Basehttps://lowpaymentfee.com/api/v1/transactions/305
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/305
- —Platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com