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 collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are paid per-request at $0.02 each using USDC on the Base network, with no API keys, rate limits, or upfront commitments required. Payment is handled via the x402 protocol: callers attach an X-PAYMENT header to each request.
The specific endpoint at `/api/v1/transactions/300` is listed as "Premium API Access" and advertises a maximum cost 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 returns application/json responses. The x402 challenge was successfully captured, confirming the endpoint is live.
The broader platform advertises categories including 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). Documentation pages exist but appear gated behind a wallet connection, so detailed request/response schemas for individual endpoints are not available from the crawl.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto prices, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting reports with micropayment billing
- —Geocoding, validation, and data conversion utilities paid per request
Fit
Best for
- —Agents and bots that need keyless, pay-as-you-go API access
- —Developers who want to avoid subscription commitments for occasional API calls
- —Web3-native applications already operating on the Base network
Not for
- —High-volume production workloads where subscription pricing would be cheaper
- —Users without USDC on Base network or unfamiliar with x402 payment protocol
- —Applications requiring detailed SLAs or guaranteed uptime commitments
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/300 \
-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 per call). However, there is no OpenAPI schema, no documented request/response formats, and all docs/pricing/README pages are gated behind wallet connection, yielding minimal usable documentation. The specific purpose of the /api/v1/transactions/300 endpoint beyond 'Premium API Access' is unclear.
Warnings
- —No OpenAPI or request/response schema available for any endpoint
- —Documentation, pricing, and README pages are all gated behind wallet connection and returned no useful content
- —The specific functionality of /api/v1/transactions/300 is undocumented — 'Premium API Access' is vague
- —The platform lists many endpoint categories but none could be verified for actual functionality from the crawl
Citations
- —All endpoints are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Payment uses USDC on Base network (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) with maxAmountRequired of 20000 base units ($0.02)https://lowpaymentfee.com/api/v1/transactions/300
- —x402 challenge returned HTTP 402 confirming the endpoint is livehttps://lowpaymentfee.com/api/v1/transactions/300