Sailfish OS is a Linux-based operating system based on free software, and open source projects such as Mer as well as including a closed source UI.

Can Sailfish OS run Linux apps?

Sailfish OS is compatible with the Android™ ecosystem, and so able to run Android apps and support Android device hardware. … App support is also offered for other Linux-based systems through AppSupport for Linux Platforms product.

Is Sailfish OS based on Android?

Sailfish OS is a modern GNU/Linux operating system which uses glibc and utilises libhybris to leverage board support packages provided by OEMs for Android. This allows Sailfish OS to be ported to (almost) any device which currently runs Android.