Checkout
Payment is handled by Lemon Squeezy, who are the merchant of record — they take the payment, handle sales tax and VAT wherever you are, and email you the licence key. We never see your card.
Activation
Open the app's License pane, paste the key, press activate. That's the whole setup. The key is stored in your Mac's Keychain, and the app re-checks it occasionally when you're online.
Moving between Macs
It's a personal licence for the Macs you own. Selling one, or setting up a new one? Deactivate from the License pane first, then activate on the other machine.
Offline
Losing your internet connection never locks you out. Only a definite “this key isn't valid” from the licence server removes an activation — a server hiccup or a flight doesn't.