Pay-per-call API platform on Base: analytics, AI, finance, and utility endpoints at $0.02 each via x402.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request 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 utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, paid in USDC on the Base network.
The specific endpoint at `/api/v1/keys/10` is labeled "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. Payment uses the x402 "exact" scheme with a 300-second timeout. No API keys or rate limits are advertised — access is gated purely by the x402 payment header.
Documentation is minimal: the landing page lists available endpoints and pricing, but there is no OpenAPI spec, no request/response schema documentation, and no usage examples. The `/api`, `/pricing`, and `/README` pages all resolve to a bare "Connect wallet" prompt with no additional content. The exact behavior and response format of each endpoint (including this one) must be discovered empirically.
Capabilities
Use cases
- —Acquiring API keys or premium access tokens via a single micropayment
- —Programmatic agent access to a suite of analytics, AI, finance, and utility endpoints
- —Pay-as-you-go API consumption without subscription commitments
Fit
Best for
- —AI agents needing instant, keyless API access via x402 payments
- —Developers who want per-request billing with no signup or rate limits
- —Web3-native applications that can pay in USDC on Base
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who prefer subscription-based flat-rate pricing
- —Applications that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/10 \
-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 payment details. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and no examples. The purpose of this specific '/api/v1/keys/10' endpoint is unclear beyond the label 'Premium API Access'. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The /api, /pricing, and /README pages contain no useful content (just 'Connect wallet')
- —The exact request body format and response schema for /api/v1/keys/10 are unknown
- —The purpose of 'Premium API Access' vs. the other listed endpoints is not explained
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/keys/10 requests up to 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with a 300-second timeouthttps://lowpaymentfee.com/api/v1/keys/10
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com