Home Assistant’s Matter Server 9.0: The Big Switch from Python to matter.js (TypeScript)

If you’ve been running Home Assistant for a while, you know the Matter integration has been a bit of a work in progress. On June 23, 2026, that changed in a big way. The official Home Assistant announcement detailed the release of Matter Server add-on 9.0, which completely replaces the underlying server software. The old python-matter-server—a Python/C++ wrapper over the CSA-certified Matter SDK—has been archived, and the new server is built on matterjs-server, powered by the TypeScript-based matter.js library.

This isn’t just a version bump. It’s a fundamental rewrite of the engine that handles all your Matter devices. Here’s what you need to know before you hit “Update.”

Why the Switch?

The old Python server served its purpose, but it had limitations. It was a wrapper around a massive, complex C++ SDK, which made it slow to start, hard to extend, and a pain to maintain. The team decided to bet on matter.js, a pure TypeScript implementation that’s already proven itself in other ecosystems like Homebridge and openHAB.

The transition has been brewing for a while. In November 2025, a donation was announced to support the creator of matter.js, Ingo Fischer, who later joined the Open Home Foundation full-time. That investment paved the way for the add-on 8.2.0 beta in January 2026, the stable matterjs-server 1.0.0 release in June, and finally the official App 9.0.0 GA you see today. The Matter 1.6.0 support landed a few weeks later in the 9.1.0 update.

This is a big deal. Matter is the 12th most-used integration in Home Assistant, running on roughly 38% of all instances according to opt-in analytics. A lot of people are affected by this change.

What You Gain

The new server isn’t just a port; it’s a significant upgrade in performance and capability. Here are the practical wins you’ll notice after the update:

1. Faster Restarts (Finally) The old server had to re-interview every device from scratch on each restart, which could take minutes. The new server uses a “last-known-address” cache and can perform partial interviews. This means your Matter devices come back online much faster after a reboot or an add-on update. If you’ve ever waited impatiently for your lights to respond after a quick restart, you’ll appreciate this.

2. Better Thread Integration The new server has “Thread-aware pacing.” In plain English, it’s smarter about how it communicates with Thread devices (like many smart sensors and locks). It reduces network congestion and makes communication more reliable, especially on larger Thread networks.

3. Improved Commissioning Security Adding new devices is safer now. The server performs checks against the Test-Net DCL (Distributed Compliance Ledger) and can verify certificate revocation status. It also supports offline commissioning using a DCL snapshot, meaning you can add a device even if your internet is temporarily down. This is a solid security upgrade for a protocol that lives on your local network.

4. OTA Updates Built-In Firmware updates for your Matter devices are now handled directly by the controller. You don’t need to rely on the vendor’s app as much, which puts more control in your hands.

5. Network Topology Visualization This is a cool one. The new server includes a web UI that visualizes your Thread and Wi-Fi network topology. You can actually see how your devices are connected, which is incredibly helpful when you’re trying to figure out why a sensor at the edge of your network keeps dropping off. It turns network debugging from a guessing game into a visual exercise.

What It Costs You

The upgrade isn’t all sunshine and roses. There are real trade-offs you need to consider.

1. Higher Resource Usage The biggest complaint is resource consumption. The Node.js runtime uses roughly twice the RAM of the old Python server, and it’s more CPU-intensive. If you’re running Home Assistant on a Raspberry Pi 3 or a low-powered mini PC, you might start hitting memory limits. You may need to add swap space or consider moving to more powerful hardware. This is a genuine consideration for a lot of DIY setups.

2. One-Way Migration This is the big one. The migration is one-way. There is no downgrade path. Once you switch to the new server, you can’t go back to the old Python version without restoring a full backup. The migration FAQ is very clear about this. Your only rollback option is a snapshot you took before the upgrade. Make sure you have one.

3. Young Codebase While matter.js itself is mature, the matterjs-server integration is new. In the first three weeks after release, there were 14 patch releases. That’s a lot of rapid-fire bug fixes. It’s stable now, but you’re still on the bleeding edge compared to the battle-tested (if clunky) old server.

4. Certification Gap The old server was CSA-certified. The new one is not yet. This doesn’t mean it won’t work, but it means it hasn’t gone through the formal certification process. For most home users, this is a non-issue. For those who rely on strict compliance, it’s something to note.

How to Update Safely: A Migration Checklist

Ready to make the jump? Here’s how to do it without pulling your hair out.

1. Take a Full Backup (Critical) Go to Settings → System → Backups and create a full backup. Store it somewhere off-device (like a network share or a USB drive). This is your only parachute. Do not skip this step.

2. Check Your Hardware Resources Before you update, check your current RAM usage in the Home Assistant System panel. If you’re consistently over 70-80% RAM, you’re going to have a bad time. Consider adding swap or freeing up memory before you proceed.

3. Update the Add-on Go to Settings → Add-ons → Matter Server. You’ll see the update available. Click update. The add-on will handle the migration for you. It will stop the old server, install the new one, and move your configuration and device data over.

4. Wait for the Full Interview When the new server starts, it needs to re-interview your devices. While it’s faster than before, it’s not instant. Give it a few minutes. Don’t start fiddling with devices or restarting the add-on during this process.

5. Test Your Devices Once the restart is complete, test a few devices. Check that they respond to commands in the UI. If something is offline, try re-adding it. The Matter Server migration FAQ has troubleshooting steps for common issues.

6. Check the New Topology UI Navigate to the Matter Server add-on’s web UI (you’ll find the link in the add-on’s “Info” tab). Explore the new network topology view. It’s worth a look just to see your network health.

7. Update Home Assistant Core The Matter integration in Home Assistant Core works best with the latest version. The HA Core 2026.7 release from July 1st includes improvements that complement the new server. Make sure you’re on the latest Core version.

The Bigger Picture

This rewrite positions Home Assistant for the future. The Matter protocol is still evolving, and the new Matter 1.6 spec brings features like NFC commissioning before power, Joint Fabric (multi-admin control), and Thermostat Suggestions. The TypeScript server is much better equipped to keep pace with these changes than the old Python wrapper was.

The move to matter.js is a clear signal that the Home Assistant team is willing to make hard, unpopular decisions (like a one-way migration and higher RAM usage) to ensure the platform stays robust and maintainable in the long run. It’s a bet on a more modular, faster, and more secure Matter experience.

For most users, the upgrade is worth it. The speed improvements and the network topology visualization alone are compelling reasons. Just make sure you have a backup and enough RAM to handle it. Welcome to the new era of Matter in Home Assistant.

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Cross-links automatically generated from SmartHome Field Guide.

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