Comparison

Home Assistant vs Z21

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Home Assistant

Control your entire smart home from one app, locally and privately. Automate devices, receive notifications, and manage your home's data securely. Integrates with thousands of smart devices and open standards.

Highlights
  • Control entire home from one app
  • Discover and configure new devices
  • Automate device actions
  • Local data privacy
  • Connect to open standards (Z-Wave, Zigbee, Matter)
  • Remote access via Home Assistant Cloud
  • Location-based automation
Features
Read full description

The Home Assistant Companion app allows you to access your Home Assistant instance on the go. Home Assistant is the smart home solution focused on privacy, choice, and sustainability. It runs locally in your home via a device like the Home Assistant Green or Raspberry Pi. This app connects to all the most powerful features of Home Assistant, - One app to control the whole home - Home Assistant is compatible with the biggest brands in the smart home, connecting to thousands of smart devices and services. - Discover automatically and quickly configure new devices - such as Philips Hue, Sonos, and IKEA Tradfri. - Automate everything - Make all the devices in your home work in harmony - have your lights dim when you start watching a movie, or turn off your heat when you’re away from home. - Keep your home’s data in the home - use it privately to see past trends and averages. - Connect to open standards with hardware add-ons - including Z-Wave, Zigbee, Matter, Thread, and Bluetooth. - Connect anywhere - If you would like to access this app while away from home, the most secure and simple way to get started is Home Assistant Cloud. The app unlocks your smartphone or tablet as a home automation tool. - Securely share your location, using it to automate heating, security, and so much more. - Get notifications on what's happening in your home, from detecting leaks to doors left open, you have full control over what it tells you. - Carplay functionality lets you open a garage or disable the security system from the dash of your car. - Build your own widgets to control any device in your home with a tap. - Integrate Home Assistant's functionality into Shortcuts, for example have your phone’s morning alarm turn on the coffee machine. - Apple Watch compatibility can show your home's temperature on a watch face or quickly activate devices. - Text or talk to your local voice assistant on your device. - Mac compatibility allows you to control your home from your desktop, but also to share data to build automation, like having your streaming lights turn on when your camera is active. Join the over 1 million users and empower your home with better privacy, choice and sustainability. Compatible with: Airthings, Amazon Alexa, Amcrest, Apple HomeKit, Apple TV, ASUSWRT, August, Belink WeMo, Bluetooth, Bose SoundTouch, Broadlink, BTHome, deCONZ, Denon, Devolo, DLNA, Ecobee, Ecovacs, Ecowitt, Elgato, EZVIZ, Fritz, Fully Kiosk, GoodWe, Govee, Growatt, Hikvision, Hive, Home Connect, Homematic, HomeWizard, Honeywell, iCloud, IFTTT, IKEA Tradfri, Insteon, Jellyfin, LG Smart TVs, LIFX, Logitech Harmony, Lutron Caseta, Magic Home, Matter, MotionEye, MQTT, MusicCast, Nanoleaf, Netatmo, Nuki, OctoPrint, ONVIF, Opower, Overkiz, OwnTracks, Panasonic Viera, Philips Hue, Pi-hole, Plex, Reolink, Ring, Roborock, Roku, Samsung TVs, Sense, Sensiba, Shelly, SmartThings, SolarEdge, Sonarr, Sonos, Sony Bravia, Spotify, Steam, SwitchBot, Synology, Tado, Tasmota, Tesla Wall, Thread, Tile, TP-Link Smart Home, Tuya, UniFi, UPnP, Verisure, Vizio, Wallbox, WebRTC, WiZ, WLED, Xbox, Xiaomi BLE, Yale, Yeelight, YoLink, Z-Wave, Zigbe

About

Z21

Control your model train layout and locomotives wirelessly from your iOS device. Manage your locomotive library, program digital components, and operate switches and signals with an intuitive touch interface. Enjoy a realistic train control experience with customizable driver cabs.

Highlights
  • Wireless control of locomotives and layout
  • Manage locomotive library with images
  • Program digital components
  • Intuitive graphic interface for switches and signals
  • Downloadable driver cabs for realistic control
  • Demo mode available
Features
Read full description

Use this app to connect to a Z21 Digital Center. A demo mode is available. With this app you can manage locomotive libraries, locomotives and locomotive functions, program digital components – and of course control all locomotives with DCC- or Motorola-decoder, as easy and convenient as is only possible with touch-technology. The digital switchboard Z21 connects your model train unit and your digital locomotives with your iOS device via WLAN. This way you can control the operation on your train layout easily and conveniently from your mobile device. Model train control was never this easy and convenient: With one swipe of your hand you can scroll to your model of choice in the locomotive library. A slight touch on the headlight symbol and the front and backlights go on. A second touch, this time on the speaker symbol, and the locomotive makes a sound. Drag your finger over the speed indicator and the train accelerates. The further highlights of the Z21-App • Control your entire layout with an intuitive, graphic interface and have easy access to the entire scope of functions of your digital locomotives. • Manage your entire locomotive-library in just one application, including individual locomotive images for an ideal overview. • Control the digital functions of your locomotives with intuitive function symbols instead of complicated key combinations. • Create a blueprint of your railway system and control your switches, signals and modules with a single click. • Download driver cabs and control your locomotives from a real train driver’s point of view.

Screenshots

Home Assistant4 screens
Z214 screens

Verdict

The call

The clearest difference is rating: Home Assistant at 4.7 against Z21's 3.8. Home Assistant also leads on in-app purchases (none vs 1) and ratings volume (4K vs 13). Z21's advantage is iOS requirement (12.0 vs 16.4). On price, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Z21 sells 1 one-off in-app purchase. Home Assistant asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Home Assistant holds the better App Store score, 4.7 against 3.8. That said, the two scores are not equally well evidenced: Home Assistant has 4K ratings behind it against 13, so its average is the more settled of the two. Written reviews point the same way: 54% of Home Assistant's written reviews are positive against 38% of Z21's.

UpkeepUpdate frequency

Home Assistant ships an update every 10 days, Z21 every 3 weeks. The most recent releases landed on October 26, 2026 and October 19, 2026 respectively.

Scorecard7 real differences · 3 level
Home Assistant versus Z21: the parameters behind the verdict, then further details
ParameterHome AssistantZ21
PriceFreeFree
Rating4.7 (4K ratings) — better3.8 (13 ratings)
Positive reviews54.3% of reviews — better38.3% of reviews
Number of ratings4K — better13
Update frequencyEvery 10 days — betterEvery 3 weeks
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, Mac, Apple Watch — betteriPhone, iPad, iPod
Requires iOS16.412.0 — better
Further details — not scored
Size229 MB232 MB
Age rating4+4+
DeveloperNabu Casa, IncModelleisenbahn GmbH

Customer experience

Home Assistant

All ratings4,010 ratings
Positive93.4%
Neutral1.6%
Negative4.9%
Written reviews514 reviews
Positive54.3%
Neutral8.6%
Negative37.2%

Z21

All ratings13 ratings
Positive69.2%
Neutral7.7%
Negative23.1%
Written reviews94 reviews
Positive38.3%
Neutral20.2%
Negative41.5%

Bugs and requests

Home Assistant

Not enough reviews yet to summarise bugs or requests.

Z21

Reported bugs

17 issues
  • App crashes on startup (white screen issue)
  • Connection drops to Z21 central station
  • Throttle display shows incorrect or blank speeds
  • Function buttons not responding properly in multitraction mode
  • Route synchronization failures across multiple control station pages
Show 12 more
  • Weichen (turnout) display showing white/blank images
  • App freezes during speed adjustment
  • Export functionality crashes (PRO version)
  • Occupancy feedback not displaying (Roco 10808)
  • iOS 14+ compatibility issues
  • Slow response times and lag
  • Layout elements jumping off-screen when editing
  • Routes highlighting incorrectly or not at all
  • Password-protected bug report zip file inaccessible to users
  • Fleischmann turntable module not available
  • Bridge modules cannot be displayed diagonally
  • Data loss after app updates

Requested features

20 requests
  • Offline locomotive database access
  • Dark mode or customizable color schemes
  • Background image support for layout design
  • Turntable/rotary module support
  • Automatic event-based control (occupancy detection, crossing automation)
Show 15 more
  • Pendulum train control functionality
  • Manual route deactivation capability
  • Larger emergency stop button
  • Locomotive database sharing between layouts
  • Multi-language support (Spanish, French, Italian, Russian, Japanese)
  • Diagonal bridge module display
  • Camera locomotive integration
  • Double slip switch operation
  • Text labeling in layout designer
  • Improved signal image selection interface
  • Vehicle filtering and categorization system
  • Windows/Mac desktop application
  • Start-destination buttons for easier route control
  • Occupancy feedback module support (Roco 10808)
  • Copy and paste functionality in layout mode

In-app purchases

None

Home Assistant

No in-app purchases

1 purchases

Z21

One-time1
  • Z21 Full Version$17.99

Questions

Is Home Assistant free?
Home Assistant is free to download, with no in-app purchases.
Is Z21 free?
Z21 is free to download, with in-app purchases available.
Which has better reviews, Home Assistant or Z21?
Home Assistant is rated higher. Home Assistant averages 4.7 out of 5 from 4K ratings, while Z21 averages 3.8 from 13 ratings.
Do Home Assistant or Z21 have ads?
Neither Home Assistant nor Z21 shows ads.
Which is updated more often, Home Assistant or Z21?
Home Assistant ships an update every 10 days, and Z21 every 3 weeks. Most recently, Home Assistant was updated on October 26, 2026 and Z21 on October 19, 2026.

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