Zigbee
Zigbee is a low-power 2.4 GHz mesh protocol (IEEE 802.15.4) that has been the workhorse of affordable smart home devices for over a decade — Hue bulbs, IKEA and Aqara sensors, and thousands of others. Devices pair to a Zigbee coordinator (a hub or USB stick), not to Wi-Fi, and mains-powered devices extend the mesh as routers.
Zigbee 3.0, current since 2016, unified the earlier profile fragmentation (ZLL, ZHA) into one certifiable standard, and its cluster library became the basis for Matter’s data model. The ecosystem’s strength is sheer device breadth and price: our dataset tracks 5,405 Zigbee devices supported by the open-source Zigbee2MQTT project alone, from flagship brands down to very cheap Tuya-made hardware.
The catch is that Zigbee interoperability is real but imperfect: manufacturers extend the standard with private clusters, so a device may pair with any coordinator yet expose its full features only on the maker’s own hub or on community-maintained platforms (Zigbee2MQTT, ZHA) where those quirks have been reverse-engineered. Zigbee also shares the 2.4 GHz band with Wi-Fi, so channel planning matters in dense environments.