What is the Matter Protocol? And Why Does It… Matter?

February 04, 2025

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What Problems Does Matter Solve?

Consider how many things in your home can be “smart,” i.e. networked in such a way that they do tasks via remote control–or even automatically. For example, a lightbulb may be set up to turn on when you walk into a room via a sensor. This is all well and good under ideal conditions, i.e. you’re using the same brand of devices with a reliable connection to the Internet. But what happens if you want to use a smart sensor from vendor X to trigger smart light Y? And what if both X and Y need to “phone home” to their respective cloud services?

Caption: Matter logo / Image Credit: Via Wikipedia

Today, it’s unlikely that devices X and Y will play well together. Even if they were somehow compatible, communicating with far-off servers and waiting for a reply means added latency and complication. If the Internet is down, your smart light may temporarily become a dumb light. If the company decides to stop supporting said smart light in the future, it then becomes a permanent dumb light, assuming it works at all.

The promise of Matter, an open-source, OSI Level 6 protocol, is that devices from different manufacturers will be able to play nicely together, and that they will be able to function without a direct connection to a remote server. Matter acts as a bridge between a device’s OSI Level 7 Application layer (the layer closest to the user) and the lower-level communication layers. Thread is the primary wireless protocol for Matter, though Zigbee devices can potentially be upgraded to “speak” Thread via a firmware update.

Matter devices use Bluetooth Low Energy (BLE) for commissioning, allowing setup via the typical smartphone and other similar devices. To communicate with the wider Internet, a bridge–i.e. a border router–is needed, such as an Amazon Alexa Show 8 or Apple HomePod. Border routers have both WiFi or wired Ethernet communication capabilities, plus a thread radio, allowing them to pass signals between the two networks. Home Assistant (HA) can be used with matter, but your HA device will either need thread radio capabilities or access to a border router on the network.

A New Protocol… to Unify All Protocols

Image Credit: xkcd

What do you get when you have 10 protocols and invent another protocol to unify all of them? 11 protocols. Sometimes, though, such an effort does work out. USB, for example, isn’t perfect, but it’s a definite improvement on the myriad of phone chargers et al that were needed not so long ago. All it took was a massive number of companies signing on to the USB Implementers Forum, decades of work… and EU legislation to get Apple on the bandwagon.

That being said, major players in the smart home market have jumped on board with Matter, including Google, Amazon, Samsung, and, yes, even Apple. In fact, Apple appears to be all in on this tech, implementing a Thread radio on its newest iPhones.

Image Credit: Jeremy Cook

Also note that Matter has has had about five years to develop. As discussed in this 2022 article, the standard was first established in December 2019 as “Project Connected Home over IP” or CHIP. More info on the spec, such as its focus on energy efficiency, is outlined here.

What about Arduino, Makers?

As a smart home consumer, if you want to start using Matter, just look for the Matter logo on smart devices, and they should play nicely together. As a developer, the protocol is open source, but there is a (potentially non-trivial) cost for certification. If you would like to experiment with the protocol, whether to implement your own one-off device, or as a precursor to something bigger, Arduino’s Nano Matter board presents an interesting alternative.

More information on the board is found in Arduino's Nano Matter documentation. I also did a live presentation on this device: Arduino Nano Matter for Easy Smart Home Automation. I hope you can check it out!