Install and forget. CashNotify lives in your macOS menu bar, so that's one less icon in your Dock. And it starts automatically, so you can just forget about it.
Receive alerts for successful and failed payments in your macOS notifications center. CashNotify always runs in the background, so you don't miss anything.
Your Stripe API key is the only thing required to get CashNotify running. It's literally one click to get it, and one click to paste it.
All data comes straight from Stripe to your desktop. No intermediate server is involved. Your Stripe API key is encrypted in your local keychain. So you know, it's safe.