Little Snitch

About

Little Snitch is a Mac app that shows where your Mac connects on the Internet and lets you decide what to allow or deny. Whenever an app tries to connect, a connection alert appears so you can approve or block it. With Silent Mode, new connections are automatically allowed at first, so you aren't interrupted and can make your final decision later.

The Little Snitch Network Monitor reveals your Mac's network activity. You can track connections to servers worldwide, see data volumes, server locations, ports, and protocols, and analyze activity in real time. Connections can be grouped by app, domain, or country, and an interactive traffic chart shows current and past activity over up to twelve months. Other features include curated blocklists, built-in DNS encryption using DoH, DoT, or DoQ, and acoustic notifications for selected connections.

You can create rules that limit which apps connect to specific servers, domains, ports, or protocols, and organize them into rule groups. Profiles can switch automatically, and a command line utility lets you change settings and export rules. Little Snitch offers a 30-day free trial. Without a license key, it runs in demo mode, which the website says provides the same protection and functionality as the full version, though the demo runs for three hours and can be restarted as often as you like.