I’ve been using Home Assistant in my home for several years now. It’s the only way I would consider having a smart home. Especially in the United States in 2025, there is absolutely no way I want to be handing over more of my personal data to the Amazons and Googles of the world, and doubly so because the enshittification train only goes one direction. Home Assistant is a breath of fresh air in the smart home space: free, open-source, and local-only.
Like a lot of open-source software, however, it can be a bit difficult to get started with Home Assistant. When I first installed it, I fumbled around the screens, fairly confused by what all the terminology meant. What’s the difference between an “integration” and a “device”? Do I need a “script” or a “scene”? How do I just make this damn button turn on the light?
With several years of Home Assistant experience behind me now, I feel like I’m in a place to help, so this post is me kicking off a guide that addresses some of the questions and misunderstandings I frequently see in Home Assistant community spaces. I believe that for complicated subjects, especially technology you’re likely to interact with on a regular basis, understanding principles and concepts is much more important than the surface-level how questions, because that deeper understanding builds a framework you’ll be able to extend as you dive further into the system.
This also means that I am, at times, likely going to fudge some details, or leave out corner cases, in the interest of providing a high-level overview. This is not a meticulous guide to the precise mechanisms of Home Assistant, or networking, or the internet. You’ll have to look elsewhere for that. I want to get you up and running with enough comprehension to solve basic problems on your own, not turn you into an IT professional.
If you’re new to Home Assistant, this guide is for you. Whether you’re still shopping around or you already got your first shipment of smart home gear, I want these posts to help you understand just how this thing works. I’m not a programmer, and I don’t think you need to be either in order to have a good working knowledge of Home Assistant.
We’ll start in this post by explaining the physical infrastructure of Home Assistant: what it means to have a “server”, how it can communicate with your smart home devices, and what to look for when buying new devices.
Just what is a server, anyway? #
If you’ve installed software before, it was likely on the device you intended to run it from. You downloaded an app on your phone so you could use it on your phone. You put Steam on your computer so you could install games on your computer. You buy Breath of the Wild on your Switch to… you get the idea.
Home Assistant is going to be a little different. You will, eventually, be able to control Home Assistant from your computer, phone, or tablet, but right now, if you tried to install the Home Assistant companion app on one of those devices, it wouldn’t get you anywhere. You first need a Home Assistant server.
Your Home Assistant server is computer dedicated to running Home Assistant. If you think about the things that you eventually want your smart home to do—turn on and off lights, set your thermostat, arm and disarm your security system, play an air-raid siren at bedtime if the cat wasn’t fed—you need a ‘central nervous system’ to be in charge of all that. Imagine if those brains lived on your smartphone. If you were away from the house, or your phone was dead, how would your home know to turn off the lights?
Big Tech companies solve this with The Cloud, which is marketing-speak for “their own computers”. If you’re away from the house and want to turn off a lamp connected to Apple HomeKit, that command goes from your phone to Apple’s computers, who then pass the message along to the HomeKit hub device in your home. Since it went through Apple’s computers, Apple got to take note of the command. And similarly, since your HomeKit hub is connected to Apple’s computers, Apple themselves could send a command you didn’t ask for. Home Assistant allows you to run a smart home without involving a
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