Pay-per-call API platform on Base network via x402 — $0.02/request in USDC, no API keys required.
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 infrastructure utilities. Every endpoint costs $0.02 per request, paid in USDC on the Base network via the x402 payment protocol. There are no API keys, no rate limits, and no subscriptions — callers simply attach an X-PAYMENT header with a valid x402 payment proof to each request.
The specific endpoint at `/api/v1/accounts/123` is listed as "Premium API Access" and returns `application/json`. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and has a payment timeout of 300 seconds.
The broader platform advertises additional 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). All are priced identically at $0.02 per call. Documentation pages exist but appear to require wallet connection and contain no visible technical detail beyond the landing page.
Capabilities
Use cases
- —Agent-driven data retrieval without managing API keys or subscriptions
- —On-demand AI inference (sentiment, summarization, classification, embeddings) paid per call
- —Fetching real-time crypto prices, gas estimates, and exchange rates
- —Geocoding and data validation as utility microservices
Fit
Best for
- —AI agents that need frictionless, keyless API access via crypto micropayments
- —Developers prototyping with low-cost, no-commitment API calls
- —Web3-native applications that already hold USDC on Base
Not for
- —High-volume production workloads where per-request pricing adds up quickly
- —Users without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/123 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint works and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages behind wallet-connect gates returned no useful content. The specific purpose of /api/v1/accounts/123 ('Premium API Access') is vague and undocumented.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) all render only a 'Connect wallet' prompt with no visible technical content.
- —No OpenAPI or schema documentation is available; request and response formats for this endpoint are unknown.
- —The purpose of /api/v1/accounts/123 is unclear — 'Premium API Access' is a generic label with no further explanation.
- —The broader platform lists many endpoints but none have documented input/output schemas.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/accounts/123
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/accounts/123
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com