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 `/api/v1/keys/61` 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 subscriptions are required — callers simply attach an x402 payment header to each request.
The platform advertises four categories of APIs: 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/request pricing.
The endpoint at `/api/v1/keys/61` returned a valid 402 challenge confirming it is live. However, the specific functionality behind this particular path is unclear — the description simply says "Premium API Access" without detailing what data or service it returns. No OpenAPI schema, request/response examples, or detailed documentation were found in the crawl. The /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Accessing data analytics and reporting endpoints without subscription commitments
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) on a per-call basis
- —Fetching real-time financial data such as token prices, exchange rates, and gas estimates
- —Using utility services like geocoding, validation, and data conversion with instant crypto payment
Fit
Best for
- —Developers who want pay-per-use API access without API key management
- —Agents and bots that can settle payments in USDC on Base via x402
- —Projects needing low-cost, no-commitment access to a variety of common API services
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Applications requiring high-throughput bulk access at volume-discounted rates
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/61 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and network. However, there is no OpenAPI schema, no request/response examples, and no documentation beyond a landing page listing endpoint names. The specific functionality of /api/v1/keys/61 is undocumented. Most crawled pages returned only 'Connect wallet' with no useful content.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The specific purpose of /api/v1/keys/61 ('Premium API Access') is not explained anywhere
- —Documentation pages (/api, /pricing, /README) returned no useful content beyond 'Connect wallet'
- —No request or response examples are available to verify what data this endpoint returns
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 in USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/keys/61
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers APIs in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com