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 broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no subscriptions required. The specific endpoint at `/api/v1/transactions/315` is listed as "Premium API Access" and returns `application/json` via HTTP POST.
The site advertises four 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 utilities (geocoding, validation, conversion, generation). All endpoints follow the same $0.02 flat pricing model.
The x402 challenge for this endpoint specifies a `maxAmountRequired` of 20000 base units of USDC (6 decimals), which equals $0.02. Payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on the Base network using the exact payment scheme. The endpoint is live and responds with a proper 402 challenge. However, documentation beyond the landing page is essentially empty (all sub-pages just show "Connect wallet"), so the actual request/response schemas for this specific endpoint are unknown.
Capabilities
Use cases
- —Accessing premium API data without needing API keys or subscriptions
- —Making one-off API calls paid per-request in USDC on Base
- —Agent-driven workflows that need low-friction, pay-as-you-go API access
Fit
Best for
- —Developers wanting zero-commitment, per-call API pricing
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto-native payment rails over traditional billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Users without USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/315 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no documentation for request/response schemas, and all doc pages are empty stubs. The specific purpose of /api/v1/transactions/315 ('Premium API Access') is entirely opaque — it's unclear what data or service it actually provides.
Warnings
- —No OpenAPI or schema documentation available — request/response format for this endpoint is unknown
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no actual content
- —The purpose of /api/v1/transactions/315 is unclear; 'Premium API Access' is a generic label with no further explanation
- —Cannot verify what data or service this specific endpoint actually returns
Citations
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge specifies maxAmountRequired of 20000 base units of USDC (USD Coin) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/315
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com