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 marketplace that offers a broad set 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 commitments required. The x402 protocol handles payment inline: callers attach a payment header to each HTTP request and receive the response immediately upon settlement.
The specific endpoint at `/api/v1/transactions/144` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per call, consistent with the site's uniform pricing. The endpoint accepts POST requests and returns `application/json`.
The broader platform advertises endpoints in 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 to view, so detailed request/response schemas are not available from the crawl.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) on a per-call basis without API keys
- —Fetching real-time crypto prices, exchange rates, and gas estimates via micropayments
- —Running geocoding, validation, or data conversion utilities with no subscription commitment
- —Exporting analytics data or generating insights reports paid per request
Fit
Best for
- —Agents or developers who want instant API access without signup or API key management
- —Low-volume or bursty workloads where per-call pricing is more economical than subscriptions
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where per-request fees add up (no bulk discounts documented)
- —Users without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/144 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documented request/response formats, and the docs/pricing/README pages all resolve to a wallet-connect prompt with no usable content. The specific purpose of the /api/v1/transactions/144 endpoint beyond 'Premium API Access' is unknown.
Warnings
- —Documentation pages (/docs, /pricing, /README, /api) all return only a 'Connect wallet' prompt — no usable technical documentation is publicly accessible.
- —No OpenAPI or JSON schema is available; request and response formats for this endpoint are undocumented.
- —The specific function of /api/v1/transactions/144 ('Premium API Access') is unclear — it does not match any of the named endpoints listed on the homepage.
- —The platform lists many endpoint categories but it is unverified whether all are actually functional.
Citations
- —Uniform pricing of $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/transactions/144
- —Platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com