You keep stumbling across the term “companion app”. This describes - in general - an app that is supplied as an accompaniment to another app or hardware. Examples include iPhone apps that function as a remote control for a specific Bluetooth speaker.
I first encountered the term companion app when I had the new Apple Watch and was at a loss to install apps on it. This is not possible via the watch itself, but via a companion app called "Watch" on the iPhone, which "pushes" the software onto the Apple Watch. That would be an example of such an additional app.
Other examples of companion apps are the watch apps from Komoot or Runtastic, which act as add-ons to the iPhone app. With the Runtastic Watch app you can go jogging without an iPhone, but in conjunction with the iPhone you can change settings and have more options for adapting your training.
At Komoot, things are even more limited. Here the watch app is only used to display distances and arrows for the next junction. The Komoot app on the Apple Watch will not work without the iPhone in your luggage. This is a companion app that cannot be used on the iPhone without its counterpart.
Another example is the Adobe Preview app, where the iOS app is the Mac-dependent app for a change. The apps on the iPhone and iPad are used here to visualize a design that you are currently editing in Adobe Photoshop on the Mac on your iPhone or iPad. So you can quickly see what the user interface looks like on the different devices. This is useful when working on the UI of iOS apps and want to check the results of your work in between.
The main application is also essential for the companion app "Adobe Preview", because Adobe Preview does not run without Photoshop.
Companion apps as an add-on for hardware
What I have come across more and more recently are companion apps that serve as help, advice or even control elements for real, physical devices. For example, the latest version of the Thermomix offers the transfer of recipes via app so that you always have your favorite selection directly in the device. But coffee machine manufacturers also use apps, for example to conveniently adjust the machine settings via the app.
In itself that's a good idea, but unfortunately I have seen too often in the past how such apps were no longer developed and then at some point they were no longer supported by iOS. The result is that, in the worst case, you can no longer operate your coffee machine ... I personally don't like to take this risk.
Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.
Did you like the article and did the instructions on the blog help you? Then I would be happy if you the blog via a Steady Membership or at Patreon would support.