across is described as '1. Bluetooth Keyboard/Mouse Emulator: across makes a Bluetooth equipped PC or Mac work as a standard Bluetooth keyboard/mouse combo. Thus, you can seamlessly/wirelessly control all your smart devices including computer, smartphone and tablet PC with the computer’s keyboard and' and is a Remote Desktop tool in the os & utilities category. There are more than 100 alternatives to across for a variety of platforms, including Windows, Mac, Android, Linux and iPhone apps. The best across alternative is KDE Connect, which is both free and Open Source. Other great apps like across are RustDesk, AnyDesk, AirDroid and Chrome Remote Desktop.