Four development platforms offer a bit of organization in a multi-screen world

By Gilly Dekel

It wasn’t a headline session, but in June of this year, Apple very quietly and subtly offered some much needed order to the world of digital devices. It started in the WWDC keynote, when the company announced the change from OS X to macOS.

Suddenly, there was a slide that laid everything out so clearly: There are four platforms — macOS, tvOS, watchOS and iOS. From the moment this slide was shown, devices were no longer called out by name. The speakers only used the platform names, and often as a group. Only once in a while did they mention iPad by name. The motive for this was most likely iPad sales numbers.

The message to developers is very, very clear: You aren’t developing apps for devices, you are developing apps — or rather, experiences — for an ecosystem, and you have to think about your experiences in the context of that ecosystem.

In order to understand how to develop for an ecosystem of digital devices, it is important to first understand the characteristics of each platform and what someone gets from it.


This is the home device. It is always on and always connected. This is the anchor device, a very dependable presence with which you can communicate. The screen size here dictates a communal experience. Several people can and are even meant to gather ’round and share this experience. This category can be generalized to “anchored devices,” including Echo, Android TV, smart TVs and smart home control centers.


The wearable is the most intimate digital interface, as it resides on your person and has a screen size that is almost solely viewed alone. The screen size also dictates very quick interactions, conveying small amounts of information that allow for a limited input. This limitation also lends itself to speed. The connectivity here is the least reliable, but the presence is the most constant, allowing the near-constant collection of data. This category can be generalized to all wearables, including Fitbit and Pebble.


This category represents the flat squares with screens we have in our lives. For simplicity’s sake, let’s call them smartphones, though we can easily generalize to include tablets as well. These devices have fairly reliable connectivity and are quite present. The smartphone is used when we are not next to a computer, so we are either in public, on the go, in a meeting or sitting at home but not next to a computer. This family can be generalized to all smartphones and tablets.


This is the computer. The main characteristic that affects interactions here is the “holy trinity” of keyboard, mouse and screen. This makes it the most comfortable device for creating content. It’s the least present device, but when we are next to it, we’re accustomed to managing our interactions from the computer interface.

For example, consider a chat application. Though you may use it on your phone on your way to your computer, it’s easier and less intrusive to continue the conversation once you sit next to the mouse, keyboard and screen combination. macOS can be generalized to any device with this three-feature combination. Tablets can also land in this category, though the fact that tablets can be found in two categories may just be their problem.

Another notable event is the advent of the personal assistant, which offers a way to interact consistently across the four platforms. This can include Siri, Alexa and Cortana.

Moving across platforms

Users are becoming highly accustomed to moving seamlessly through the ecosystem of four platforms. This poses a challenge for developers, who need to understand how to deliver the best experience on each in a way that makes it easy to move between them. How do you deliver the correct, most relevant experience to the correct device? What does your user expect to achieve in each of them? What does your user expect when moving between two devices?

We used to think the challenge of developing apps would be the upkeep of two code bases for iOS and Android. This seems like a small problem now. Today, the challenge is taking into account the characteristics of each platform and delivering a relevant experience to a person on the other end of it. The four platforms make this thought process a bit more organized, and this taxonomy will help developers deliver great experiences to their users.

Written By

Gilly Dekel

Product Manager - Mobile Development on Bluemix at IBM

I have been developing mobile applications for a while now. In doing this, I have touched upon development in various platforms, but have been mainly focused on the various iOS devices - iPhone, iPad and iPod touch - since iOS 2.0 came out and changed everything. Over the course…