NetBlocker is a deliberately simple outbound firewall for Apple silicon Macs. Drag an app into the list to block its new network connections. NetBlocker also discovers and displays related helpers, XPC services and background processes, so one rule covers more than the visible app. There are no connection-by-connection popups, accounts or subscriptions. It includes a 7-day free trial, costs €4.99 once and comes with a 30-day money-back guarantee.
