Pay-per-call API platform on Base via x402 — data, AI, finance, and utility endpoints at $0.02/request.
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, payable in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The specific endpoint at `/api/v1/charges/122` is labeled "Premium API Access" and returns a standard x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme, with a 300-second timeout. The endpoint accepts HTTP POST and returns application/json.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The actual functionality behind "Premium API Access" (as opposed to the named endpoints like sentiment analysis or geocoding) is not described anywhere in the crawled content.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates via micropayment
- —Running geocoding or data validation tasks with per-request billing and no subscription
Fit
Best for
- —AI agents that need keyless, pay-as-you-go access to diverse API endpoints
- —Developers prototyping with low-cost, no-commitment API calls on Base
- —Web3-native applications that can settle USDC payments natively
Not for
- —High-volume production workloads where per-request pricing at $0.02 adds up quickly
- —Users who need detailed API documentation, SDKs, or OpenAPI specs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/122 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, and the landing page lists available endpoints with pricing. However, documentation pages are empty (just 'Connect wallet'), there is no OpenAPI spec, no request/response schemas, and the specific 'Premium API Access' endpoint's functionality is undefined. This is effectively a stub listing.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) return no useful content — only a 'Connect wallet' prompt.
- —No OpenAPI or schema documentation available for any endpoint.
- —The 'Premium API Access' endpoint at /api/v1/charges/122 has no description of what it actually returns or what input it expects.
- —The broad catalog of 16+ endpoints listed on the homepage cannot be individually verified from the crawl data.
Citations
- —All endpoints priced at $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 with 300s timeouthttps://lowpaymentfee.com/api/v1/charges/122
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Docs, API, pricing, and README pages render only 'Connect wallet' with no documentation contenthttps://lowpaymentfee.com/docs