All Matter-certified devices in your local area network (LAN) will work smoothly even when your home internet goes offline. Matter allows effective communication directly between devices, without the need for a specific ‘forwarding’ device. For example, a Matter smart switch or sensor can turn on/off a Matter bulb directly without being connected to a cloud service, or other specific action. Once configured, communication and control between Matter devices can be achieved directly on the local network.
https://www.wired.com/story/what-is-matter
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