HomeKit

HomeKit, also known as Apple Home, is a software framework and communication protocol developed by Apple Inc. that lets users configure, communicate with and control smart-home appliances using Apple devices. It provides users with a way to automatically discover such devices and configure them. By designing rooms, items and actions in HomeKit, users can enable automations in the home through a voice command to Siri or through the Home app. With HomeKit, developers are able to create complex applications in order to manage accessories at a high level.

Overview
HomeKit was first introduced on iPhones and iPads on September 17, 2014, with iOS 8. The framework allowed third-party apps to interface with HomeKit devices using Siri and allow remote access through home hubs.

HomeKit was created to make tasks inside the home easier and provide users with methods and tools to change and adapt certain home capabilities to their specific desires. HomeKit manages connected home appliances through the HomeKit Accessory Protocol (HAP). Messages from HomeKit are continuously sent to powered devices, which incorporate fields which recognize the specific accessory and what category it is under. Each category has a code that is used to identify what the device is. It also identifies with the Global State Number (GSN). This number is increased each time that the state of the accessory is altered. Like most Apple devices, Apple Continuity Protocols are used. Continuity protocols consist of wireless technologies, such as Bluetooth and Wi-Fi. They can be conducted through device-to-device connection.

HomeKit uses Bluetooth and Wi-Fi protocols. On HomePods and some Apple TVs, Thread is also used to connect and communicate with devices. Manufacturers of HomeKit-enabled devices are required to enroll in the MFi Program. Apple also used to provide documentation for creating non-commercial HomeKit accessories to any member of the Apple Developer Programme. Initially, all HomeKit-based products were required to include an encryption co-processor. The latter requirement was later changed in iOS 11, which added support for software-based authentication. Equipment manufactured without HomeKit support can be enabled for use through a "gateway" product, such as a bridge that connects those devices to the HomeKit service.

HomeKit primarily competes with smart home standards from Amazon and Google. As of October 2019, Apple lists 450 devices compatible with HomeKit, compared to 10,000 for Google and 85,000 for Amazon.

Home app
The Home app, which unifies all devices into one app, was introduced on iPhones and iPads on September 13, 2016, with iOS 10, and on Apple Watches with watchOS 3. The app also added support for automations using a home hub, and preprogrammed "scenes", which can set multiple devices using a single command. With iOS 16, Home received a major redesign which aimed to make the app easier to navigate, and the architecture of the program was rebuilt from the ground up to be more efficient for users with multiple HomeKit enabled devices. HomeKit toggles can also be added to the Control Center, allowing control over connected devices without having to use Siri or open the Home app. iOS 18 brings guest access, hands-free unlocking of locks, in-app electricity usage integration, and the ability to unlock locks using Express Mode with an iPhone that is out of battery.

The Home app was introduced on Macs with macOS 10.14 Mojave, which was released on September 24, 2018.

Apple TV & HomePod
Fourth-generation and newer Apple TVs can control HomeKit devices using Siri voice commands. tvOS 14, which was released on September 16, 2020, added direct control of HomeKit devices in Control Center and camera feeds and picture-in-picture monitoring for HomeKit-enabled security cameras. Neither the HomePod nor Apple TV can unlock or open secure appliances like locks.

The HomePod supported HomeKit at launch in February 2018, as did the HomePod Mini in 2020. They lack a graphical user interface to control HomeKit devices and instead uses Siri voice commands.

Home hubs
As of iOS 16, Apple TVs (4th generation or newer) and HomePods are fully supported as home hubs to control HomeKit appliances remotely, grant guest access, and set up automations. Support for Thread is included in the HomePod Mini, second generation HomePod and Apple TV 4K (2nd generation and later). Automations based on temperature and humidity are supported by the HomePod Mini and second generation HomePod.

iPads supporting iOS 10 or later can be used as a home hub but were deprecated with iPadOS 16; iPads do not support Matter and new architectures that were extended to Apple TV and HomePod, but retain all functionality introduced before iPadOS 16. The third-generation Apple TV only supports remote access and supported automations before iOS 10.

Coming in iOS 18, users will be able to choose which device is their home hub.

Device categories
HomeKit currently supports the following device categories (an extended list):

• Air conditioners

• Air purifiers

• Bridges

• Cameras

• Doorbells

• Dehumidifier

• Doors

• Fans

• Faucets

• Garage door openers

• Humidifiers

• IP Camera

• Lights

• Locks

• Outlet

• Programmable Switch

• Audio/video receivers

• Range Extender

• Routers

• Robot vacuums in iOS 18

• Security systems

• Sensors

• Shower Systems

• Smoke Alarms

• Speakers

• Sprinklers

• Switches

• Thermostats

• Televisions

• Video Doorbell

• Windows

Garage doors, locks, security systems, and windows are categorized as secure appliances, and require a device with authentication such as an iPhone or iPad to unlock.

Matter support
On December 18, 2019, Apple announced that it will be working closely with Samsung, Amazon, and Google to create an open standard for smart home automation called Matter. Matter aims to reduce fragmentation across different vendors, and achieve interoperability among smart home devices and Internet of things (IoT) platforms from different providers. The project was delayed to fall 2022 due to "unprecedented interest" by the Connectivity Standards Alliance (CSA). Version 1.0 of Matter was published on the October 4, 2022. Matter has been supported by Apple devices since iOS 16.1 and its forks.