KaiOS is a feature-limited or entry-level mobile device (also called dumb phones) operating system that incorporates the functionality of a smartphone or smartphone into a entry-level phone and therefore much cheaper.
It is a Linux-based operating system like Android, uses HTML5-based applications and is intended to be used on devices with a physical keyboard and without a touch screen.
Despite its limitations and lightness, KaiOS supports 4G LTE, VoLTE, GPS and Wi-Fi networks and applications such as WhatsApp, Twitter, Facebook or YouTube can be installed.