Why I’m a fan of light switches …

About functional simplicity in products

Nikolas Klein
2 min readSep 13, 2015

Light switches are stunning interfaces! Especially from a user-experience point of view. They are designed to do exactly two things: Turning the light on and turning the light off.

I call this functional simplicity.

Functional simplicity in products or interfaces enhances the experience. You can find a lot of good examples for great functional simplicity when you look at microinteractions. These small interaction details mostly have this one thing in common. They are designed to do a simple task — and doing this extremely well.

Great collection of microinteractions. Video done by Smart Design

But since microinteractions are the smallest parts of an interface, they nearly always do just one thing anyway. So when we look at bigger products, we have to look further to find good examples for functional simplicity.

Functional Simplicity in Products

A trend in the last years has been that multi-purpose apps have been unbundled to single-purpose apps (e.g. Facebook with Messenger or Google with Google Drive). With this way different use cases can be addressed and the experience enhanced. Packing all in one can lead to a feature creep.

These are most of the time damned to fail.

Let’s assume we are building an app with two different main functions. When explaining what the app actually does it goes like “It can do this — but it also can do that. And later maybe we’ll add this as well.” For interaction designers this should ring a bell.

Evaluate the use cases of these functions. If they happen to be too apart from each other, you may better go with multiple single purpose apps. This way, while keeping a functional simplicity, you can create the best experience for the user.

Portals haven’t worked on mobile: in many ways, the phone itself is the portal.

Taylor Davidson also wrote about mobile single-purpose app strategies. What he is describing here, is that users are pretty familiar with choosing from different apps. They do it multiple times every day. That means the phone itself is the portal to your tasks. If you put two main functions, which have different use cases, into one app, you are creating an extra and unnecessary step for the user:

single-purpose app: open › do

multi-purpose app: open › navigate through functions › do

Selecting your task from the home screen is faster and more convenient for a user. This might not seem much, but in a time where it can also be, that the act of opening apps might vanish, it can make the essential difference.

Good examples for a functional simplicity are the IFTTT DO apps, Vine or the simple yet successful YO app.

They do one thing alone, but extremely well. This simplicity is what we should strive for in digital and physical products.

Thanks for Reading! #functionalsimplicity

Written by Nikolas Klein, 09|2015



Nikolas Klein

Product Designer at Figma - Using products should feel like slicing tomatoes with a really sharp knife.