KDE Connect is on all major platforms.
KDE Connect Desktop Component is available in all major distribution packet managers. Non-Plasma users like Gnome and AppIndicator supported desktop users have various ways to enhance their experience like GSConnect which implements the KDE Connect protocol in GNOME and uses our android application, and indicator-kdeconnect is available for AppIndicator supported Desktops.
Instructions for Linux
KDE Connect Android App is available on both Google Play Store and on the Open Source F-Droid Store.
Get it from Play Store
KDE Connect is available on SailfishOS and the KDE Connect Team is working on bringing connect to other linux based phones.
Get it for SailfishOS
KDE Connect works fairly well on Windows. Build following the detailed instructions.
Instructions for Windows
A mobile friendly interface, targeted at mobile Linux Platforms such as Plasma Mobile, is also available.
Instructions for Mac OS
KDE Connect Source Code can be viewed using cgit. Source Code is available for all OS.
Browse Code