Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints gated by the x402 payment protocol. This specific endpoint (`/api/v1/lab/results/32`) is listed as "Premium API Access" and returns JSON results upon payment. The site offers endpoints across several categories: Data & Analytics (metrics, reports, 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).
Payment is settled on the Base network using USDC (contract `0x8335…2913`). The x402 challenge for this endpoint specifies a `maxAmountRequired` of 20,000 base units, which at 6 decimals equals $0.02 per request — consistent with the site's advertised flat pricing of $0.02/request across all endpoints. No API keys are required; access is granted immediately upon valid x402 payment. The site claims no rate limits.
The specific resource at `/api/v1/lab/results/32` appears to be a lab-results endpoint, but no further documentation about its request schema, expected input parameters, or response format was found in the crawl. The endpoint is live and returning a proper 402 challenge. The broader platform is a demonstration of low-fee micropayment APIs, but documentation beyond the landing page is sparse (pricing, README, and /api pages all just show a "Connect wallet" prompt).
Capabilities
Use cases
- —Accessing premium data results without subscription or API key management
- —Demonstrating x402 micropayment integration for per-call billing
- —Programmatic retrieval of lab results data via crypto-settled requests
Fit
Best for
- —Developers exploring x402 payment protocol integration
- —Agents that need keyless, pay-per-use API access on Base
- —Low-volume consumers who want no-commitment API access
Not for
- —High-volume consumers who need bulk pricing or subscription discounts
- —Users without USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/lab/results/32 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing. However, there is no documentation for this specific endpoint's input/output schema, no OpenAPI spec, and the crawled pages beyond the landing page are empty (just 'Connect wallet'). The purpose of '/api/v1/lab/results/32' is unclear — it could be sample/demo data. Effectively a stub listing.
Warnings
- —No documentation found for /api/v1/lab/results/32 — purpose and response format are unknown
- —No OpenAPI or schema definition available for any endpoint on the site
- —Pricing, README, and /api pages returned no useful content (just 'Connect wallet')
- —The endpoint path suggests a specific resource ID (32) which may be demo/sample data
Citations
- —The site advertises $0.02/request flat pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)https://lowpaymentfee.com/api/v1/lab/results/32
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com