Can I run Matter through Home Assistant without buying a hub?
Yes for Matter-over-Wi-Fi devices, with a caveat for Thread. Home Assistant's Matter integration runs the open-source Matter Server as its own controller, so no commercial hub is required and control stays local. Matter-over-Thread devices still need a Thread border router on the network. Home Assistant can be that border router using Connect ZBT-1, ZBT-2 or SkyConnect hardware with the OpenThread Border Router add-on.
Last checked: against Home Assistant Matter integration documentation and Thread integration documentation
Where the "no hub" claim is true
Home Assistant is itself the Matter controller. Its documentation describes the Matter Server as "the controller software as a separate process" that "connects your Matter network (called Fabric in technical terms) and Home Assistant." Installing the Matter integration on a standard Home Assistant OS setup installs that server for you.
For a Matter-over-Wi-Fi or Matter-over-Ethernet device, that is the whole requirement. No HomePod, Echo, Nest Hub or SmartThings hub is involved, and Home Assistant's documentation states that Matter products "run locally and always allow local control, with device control done without the need for any internet connection or cloud services."
Where it is not true: Thread
A Matter-over-Thread device speaks Thread, not Wi-Fi, and needs a Thread border router to reach the IP network. Home Assistant's Matter documentation names the qualifying options explicitly rather than accepting any border router: "Nest Hub (2nd Gen) or Nest Wi-Fi Pro or Home Assistant with the Home Assistant OpenThread Border Router app."
So the accurate framing is that Home Assistant removes the need for a commercial ecosystem hub, not the need for Thread radio hardware. If every Matter device you plan to buy is Wi-Fi, there is nothing else to buy. If any of them is Thread, something in the house must have a Thread radio.
Making Home Assistant the border router
Home Assistant's own documentation covers the software route: Connect ZBT-1, ZBT-2 or SkyConnect hardware running the OpenThread Border Router add-on turns the existing install into a border router. Home Assistant Yellow's built-in radio can serve the same purpose.
One caveat is documented at source rather than inferred: Home Assistant describes the integration of its own Thread border router with Matter as work-in-progress.
The status warning Home Assistant itself prints
The documentation tells adopters plainly that they "are an early adopter, both on the hardware side and on the software (controller) side" and may encounter "compatibility issues or features that are still missing." That is Home Assistant's characterisation of its own Matter support, not an outside assessment.
For context on maturity: Matter 1.0 was published in October 2022, and the Matter integration arrived in Home Assistant release 2022.12.
How this compares with the commercial ecosystems
Home Assistant's advantage here is scope rather than mechanism. The commercial platforms each publish a finite list of Matter device types they will accept — Alexa lists 24 device types, and Apple Home publishes two lists that disagree. Home Assistant's constraint is instead the maturity of its integration for a given device. Being on multiple fabrics at once is available either way, since multi-admin is a property of the standard.
Related questions
What is the Matter Server?
Home Assistant describes it as the controller software running as a separate process, connecting the Matter network — called a fabric in technical terms — to Home Assistant. On a standard Home Assistant OS install, adding the Matter integration installs the official Matter Server add-on automatically.
Does Matter through Home Assistant work without internet?
Home Assistant's documentation states that Matter products run locally and always allow local control, with device control done without the need for any internet connection or cloud services.
What is needed to commission a Matter-over-Wi-Fi device?
Home Assistant's documentation states the phone must be on the same 2.4 GHz network as the devices during commissioning.