# Lions Operating System 7 Hacker News commenters recommended Lions Operating System and 0 criticized it, November 2025 to November 2026. It was recommended in 1 of 13 months. **Verdict:** Research operating system built on the seL4 microkernel, recommended for its security focus, formal verification and reliability. Critics say it is not yet a daily driver. ## Why people recommend it - Security and formal verification (2 comments): "Its just the fastest, safest and most reliable possible operating system, giving you more formal guarantees then literally anything else" ([source](https://news.ycombinator.com/item?id=46012758)) "The primary focus of Lions/seL4 is security, and formal verification of it." ([source](https://news.ycombinator.com/item?id=46022252)) - Reliable, well-engineered design (2 comments): "Its just the fastest, safest and most reliable possible operating system, giving you more formal guarantees then literally anything else" ([source](https://news.ycombinator.com/item?id=46012758)) "How can a project do everything so right?" ([source](https://news.ycombinator.com/item?id=45997991)) - A true OS, not Linux (2 comments): "At least someone hasn't complained about it being 'unix like'" ([source](https://news.ycombinator.com/item?id=46000069)) "Finally an OS that is really an OS and not a linux distro" ([source](https://news.ycombinator.com/item?id=46005557)) ## What people warn about - Not yet a daily driver (1 comments): "interesting, but can't be a daily driver for me" ([source](https://news.ycombinator.com/item?id=46006248)) ## Alternatives hackers recommend - [Windows](https://hackerapproved.com/p/windows.md): 1287 recommend - [macOS](https://hackerapproved.com/p/macos.md): 1041 recommend - [Linux](https://hackerapproved.com/p/linux.md): 745 recommend - [Haiku](https://hackerapproved.com/p/haiku-os.md): 115 recommend - [NetBSD](https://hackerapproved.com/p/netbsd.md): 100 recommend ## Cite as Hacker Approved, "Lions Operating System", https://hackerapproved.com/p/lions-operating-system/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).