Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/keys/56` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each request.
The platform advertises four categories of endpoints: 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 listed endpoints share the same $0.02 per-request pricing.
The `/api/v1/keys/56` endpoint itself is live and returns a proper 402 challenge with x402 version 1. However, the exact functionality behind this particular path ("Premium API Access") is not documented beyond its title. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawled pages. The site's non-API pages (pricing, README, /api) all resolve to a minimal "Connect wallet" prompt, providing no additional documentation.
Capabilities
Use cases
- —Agents that need on-demand API access without managing API keys or subscriptions
- —Programmatic access to AI inference (sentiment, summarization, classification, embeddings) with per-call billing
- —Fetching real-time financial data (prices, exchange rates, gas estimates) via micropayments
- —Utility operations like geocoding, validation, and data conversion paid per request
Fit
Best for
- —AI agents needing frictionless, keyless API access via x402
- —Developers who want pay-as-you-go pricing with no minimums
- —Applications requiring low-cost micropayment-settled API calls on Base
Not for
- —High-volume production workloads needing guaranteed SLAs and detailed documentation
- —Users who need well-documented request/response schemas before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/56 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no OpenAPI spec, no request/response schema, no documentation of what 'Premium API Access' at /api/v1/keys/56 actually returns, and no usage examples. The crawled pages beyond the homepage are empty wallet-connect stubs. The listing is effectively a stub with pricing info only.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —The exact functionality of /api/v1/keys/56 ('Premium API Access') is undocumented — it is unclear what data or service it provides
- —Non-root pages (/pricing, /README, /api) returned only 'Connect wallet' with no useful content
- —No request body schema or response format is documented anywhere
Citations
- —The endpoint returns a 402 challenge with x402 version 1, accepting USDC on Base networkhttps://lowpaymentfee.com/api/v1/keys/56
- —maxAmountRequired is 20000 base units of USDC (6 decimals) = $0.02 per requesthttps://lowpaymentfee.com/api/v1/keys/56
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Payment is settled to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/keys/56