LuLu – a free, open-source firewall for macOS.

Most apps connect to the internet without ever asking you. LuLu changes that. Built by Objective-See, it monitors every outgoing connection and asks for your permission before letting any app go online. It runs quietly in the menu bar and is simple enough for everyday users.

Key Features:

• Outgoing Connection Alerts: Get notified the moment any app tries to connect to the internet.
• Allow or Block: Choose which apps are allowed online and which are not, with a single click.
• Rules System: Set permanent rules for apps you trust so you are not asked every time.
• Menu Bar Access: Runs quietly in the background with a simple menu bar icon.
• Open Source: Fully transparent code — no hidden data collection, no ads, no upsells.
• Free Forever: No trial period, no subscription, no paid upgrade required.