Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints spanning data analytics, AI/ML inference, finance/crypto data, and utility services. All endpoints are paid per-request using USDC on the Base network at a flat rate of $0.02 per call. The x402 protocol eliminates the need for API keys, accounts, or subscriptions — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/charges/300` is listed as "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. The payment scheme is "exact" with a 300-second timeout, settling to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3.
The broader platform advertises 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 (geocoding, validation, conversion, generation). Documentation pages exist but appear to require a wallet connection and contain no visible technical content, so the actual request/response schemas for these endpoints are unknown.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification) without managing API keys
- —Fetching real-time crypto prices, gas estimates, or exchange rates with per-call payment
- —Running geocoding or data validation as a utility service from an autonomous agent
- —Exporting analytics data or generating insights on a pay-as-you-go basis
Fit
Best for
- —AI agents needing keyless, pay-per-call access to diverse API endpoints
- —Developers who want to avoid subscription commitments for low-volume usage
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/300 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, documentation pages are empty (wallet-gated), there is no OpenAPI schema, no request/response examples, and the actual functionality behind '/api/v1/charges/300' is unclear beyond the label 'Premium API Access'. The broader platform lists many endpoints but none have documented schemas.
Warnings
- —Documentation pages (/docs, /pricing, /api, /README) all render only a 'Connect wallet' prompt with no visible technical content
- —No OpenAPI or schema documentation available for any endpoint
- —The specific purpose of /api/v1/charges/300 ('Premium API Access') is not explained — it is unclear what data or service it returns
- —Request and response formats are entirely unknown; example payloads cannot be provided
Citations
- —Flat pricing of $0.02 per request across all endpointshttps://lowpaymentfee.com
- —No API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/300
- —Endpoint categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com