Until Little Snitch 4, it controlled network traffic by registering kernel extensions through the standard application programming interface (API) provided by Apple, but for its 5th release it switched to using Apple's Network Extensions due to the deprecation of Kernel Extensions on macOS Catalina. Unlike a stateful firewall, which is designed primarily to protect a system from external attacks by restricting inbound traffic, Little Snitch is designed to protect privacy by limiting outbound traffic. It is produced and maintained by the Austrian firm Objective Development Software GmbH. It can be used to monitor applications, preventing or permitting them to connect to attached networks through advanced rules. Little Snitch is a host-based application firewall for macOS.
