The Home Assistant Matter Server app: version 9 and matter.js

The Matter Server app is the part of Home Assistant that does the controller work for Matter. Its documentation records a major change: from version 9.0.0 the app runs a different server, built on matter.js, and the older Python version of the server is no longer included. This piece summarises what the project says about that change. We have no release date for 9.0.0 from the pages we read, so we give none, and the project's pages are the authority.

What changed

The app's documentation says that from version 9.0.0 the only server inside the app is the matter.js one. The older Python server has been taken out, and data held by the earlier setup is carried over by itself, so there is nothing to do by hand. The page also warns you to take a complete backup first, since the move to a new server is a big one, and suggests leaving the Supervisor's backup option on during the update so that you can go back if needed.

The old server's own repository says the same from the other side. Its page says the server was rewritten and now lives in a project called matterjs-server. The last release of the Python server, its libraries and its container image was 8.1.2, and users are asked to move across promptly because nothing further will be published or supported.

What did not change

• The way you use it. You still install the Matter integration, which installs or connects to the server. Home Assistant's Matter page still describes the integration talking to a Matter Server over a WebSocket.
• Home Assistant OS as the supported route. The page recommends it and says it is the only supported option.
• What the server is for. It is the Matter controller, the thing that holds your fabric and talks to devices. Our piece on the controller, the app and the companion shows where it sits.

Version numbers you will meet

Two numbering schemes appear in the documentation. The app has its own version, now 9.x, and the Matter integration page refers to it in its note on cameras (Matter 1.5 and later), which asks for app version 9.3.0 or higher. For a container, the same page names 1.5.0 as the lowest server version. These look like two numbering schemes, the app's own and the standalone server's, so read a version in a feature note against the way you run Matter: an app version if you use the app, a server version if you use a container.

The app's settings

The app's documentation lists options. In plain terms:

• Beta. Fetches the newest matter-server release from the npm registry at start-up and uses it in place of the bundled copy, falling back to the bundled copy with a warning if that fails. The page notes that the flag keeps its earlier value across the update, so anyone who switched it on when the matter.js server was a beta will still have it on. Turn it off if you want only released versions.
• Pinning a version. A setting installs a specific matter-server version. It ignores versions of 3 and above that belong to the Python server.
• Time sync. The server can send the current time to devices: automatically when the host clock is synchronised, always, or never.
• Fabric label. By default it uses the Home Assistant home name. Pinning a label helps if several Home Assistant installations use the same server.
• Bluetooth. An option exposes a proxy so the Matter integration can commission over Home Assistant's own Bluetooth. An older adapter setting is marked deprecated.
• Test network ledger. A setting enables the test network of the compliance ledger for root certificates, over-the-air updates and device information. The documentation gives no other guidance, so leave it off unless you have a reason.
• Extra arguments and environment variables. Advanced.

What to do before you update

1. Read the current app documentation, not this summary.
2. Make a full backup and keep the Supervisor's backup option on.
3. Note whether the Beta flag is on and whether you want it to be.
4. Check that the Matter devices you rely on are in the list afterwards, and keep the setup codes of any device you may need to add again.
5. If you run the server in a container, read the new project's instructions, since the Python container image no longer receives updates.

Where to ask

The documentation points to the Home Assistant Discord server, the community forum and the subreddit for questions, and to the project's GitHub for bugs. The old server's page asks that Home Assistant user support requests go to those channels, not to its own issue tracker.

This piece summarises published documentation, read on 13 November 2026. It is not based on testing.