Matter controller
A Matter controller is the software brain that commissions Matter devices onto its fabric and controls them: Apple Home (via a home hub), Google Home, Amazon Alexa, SmartThings, Home Assistant, Hubitat, or Homey. Every Matter setup needs at least one, and the controller — not the device — decides which device types and features you can actually use.
The controller holds the fabric’s credentials, runs automations, and provides the app and voice interface. In most consumer ecosystems the controller function lives in a hub-like device that stays home and online: an Apple TV or HomePod for Apple Home, a Nest hub or speaker for Google, an Echo for Alexa. Home Assistant, Hubitat, and Homey run the controller on the hub itself.
Controllers differ meaningfully in coverage. A device type added in a recent Matter release may be supported by one ecosystem and ignored by another for a year, and features like a lock’s user codes or a thermostat’s schedules are exposed unevenly. This is why “Matter-certified” answers only half of “will it work with my setup” — the other half is the controller, which is what our per-hub compatibility pages are for.