Safing is an Austrian software company that develops Portmaster, a free and open-source application firewall for desktop operating systems. Portmaster operates at the network level on individual devices, providing users with visibility into all outgoing and incoming connections made by applications installed on their computer. The core functionality of Portmaster includes real-time network activity monitoring, system-wide tracker and advertisement blocking, and granular per-application firewall rules. Users can configure global network policies as well as application-specific rules, such as blocking internet access entirely for certain apps, restricting peer-to-peer connections, or filtering connections by geographic region. Portmaster is available for Windows and Linux (Debian/Ubuntu and Fedora distributions) and is distributed as a free download. A paid tier, Portmaster Pro, is offered at a subscription price, providing additional features beyond the free version. Safing has partnered with IVPN, a VPN provider, as noted in a December 2024 blog post describing a new collaborative chapter between the two companies. The company maintains a public blog, podcast, and video content to communicate product updates and development roadmaps with its user community. The product is targeted at privacy-conscious individual users seeking greater control and transparency over their device's network activity. Portmaster has been featured in publications and channels focused on open-source software and digital privacy, including It's FOSS, PrivacyTools, and gHacks.