Thread border router
A Thread border router is the device that connects a Thread mesh to your regular Wi-Fi/Ethernet network, forwarding IPv6 traffic between the two. Without one, Matter-over-Thread devices cannot be commissioned or controlled. It is a built-in function of many hubs and speakers — Apple TV 4K, HomePod, Nest Hub, Echo (4th gen), SmartThings Station — not a separate box you buy.
The border router does routing, not translation: Thread devices already speak IPv6, so the border router simply forwards packets between the 802.15.4 mesh and your LAN. Any device on your network can then reach a Thread sensor directly, which is what makes Matter-over-Thread control local and fast. One border router is enough, but several provide redundancy and better radio coverage — the mesh uses whichever is closest.
Since Thread 1.3, credential sharing is standardized, so border routers from different vendors can share one Thread network rather than each spinning up its own; ecosystems handle this with varying grace as of mid-2026, and a device still belongs to a Matter fabric per ecosystem regardless. If you are deciding whether you need one at all, the short version: only Matter-over-Thread devices require it; Wi-Fi and Ethernet Matter devices work without.