A UX designer design apps and websites. They’re the one who determines what each screen looks like, the interactions on that screen, the flow between screens, the colors and typography.

When doing this they are trying to solve a problem. A user problem. For example, in a music app, a user wants to browse albums, find an album of interest, and play that album or a song from that album.

What do the screens look like when a user does this? The UX designer determines this.

In general, they're responsible for the overall User Experience (UX).

It's easy to think about it in terms of

Overall Flow
Page Layout
Interaction Design
Visual Design

It's easy to think about UX design in these buckets, but there is overlap. For the sake of covering what a UX designer does, I'll stick to these groupings. It'll help you get the overall sense of what a UX designer does and how one might approach the craft.

A UX DESIGNER SOLVES PROBLEMS

Before we dive into each of the buckets, it's worth mentioned the concept of problem solving. This is really what a UX designer does. They are given a problem and they have to solve it.

I know that's high level, so let me use an example to help flesh it out.

Let's Use Music Apps As An Example

In music apps, a user wants to search for an album and play songs from that album. That is considered the problem

The UX designer then determines what those screens look like that allow a person to browse through music, find what they are looking for, and play specific songs.

Seems straightforward to start. But I'll use music apps as an example throughout this post to illustrate the above buckets.

The importance of understanding this is a problem they are solving is to distinguish it from just designing for fun. There are lots of cool and fun ways to design music apps, but when you look at it through the lens of:

“How Do I Create An Easy To Use Experience That’s Also Engaging?"

it starts to shape up the solution. Let's break each down:

Overall Flow In UX Design

This is going from one screen to another within an app. A simple way to think about it is in terms of pages. For example if you're on the Browse page in Spotify and you click on an album cover you go to the Album page.

Browse is a page, and so is Album. How you go from one page to the other is the flow.

The most common way to navigate around an app is - navigation. In apps, this is generally a navigation bar at the bottom. Let's look at the navigation UX for Spotify, Apple Music, and Amazon Music.

A UX Designer determines the navigation of the app

If you look at their navigation, Spotify has

Home
Search
Your Library

Compare this to Apple Music which has:

Home
Browse
Radio
Library
Search

And Amazon Music has

Home
Find
Library
Alexa

All three are ways to navigate the app. It's how you get around from one part of the app to the other. Of course there are ways of navigating.

In any of the above apps, if you're on the browse/Home Screen and you click album art you are taken to the Album page. Going from one page to the next is what is meant by UX flow.

Which One Is Right?

Part of what a UX designer does is determine the right navigation. At Spotify they decided one way, and at Apple they decide another way. A number of factors go into the decision making such the overall look and feel, features, design philosophy, business goals, and good ole fashioned corporate politics (yeah I hate to admit it but it's true).

Each UX designer came to their own conclusion based on all the factors above. It's not so much that one is right and the other is wrong. It's more so, which one is best for each company.

For example, Apple Music wants to make sure its users are aware of and go to Radio. So it's right in the middle and easy to get to. You can't miss it.

Amazon Music being Amazon, has Alexa. It's a key part of their ecosystem so it's right on the navigation bar as well.

UX Flow

If you think about general pages as the chunks the flow is how do get from page to page. This is usually the first step in what a UX designer does.

Next, a UX design determines the layout of each page.

Layout Design In UX Design

Next if we look at each page, a UX designer has to determine what elements go on that page and how they are laid out.

In our music example, each album page in Spotify, Apple Music, and Amazon Music have

Album art
Artist Name
Release Year
Play button
Song Titles
Shuffle
Save / Add

And of course a lot of other controls and content. Spotify, Apple, and Amazon all have similar content but also varying features that make them unique.

The UX designer is responsible for deciding how those elements are laid out on the screen. They may ask questions like:

Should the Album art take up most the screen
How prominent should the play button be?
How important is it to emphasize when the album was released

And many more questions to help determine how the elements should be laid out.

Interaction Design In UX Design

Once the general layout of each page is done, the UX designer determines the on page interactions. After all each page can't just be static. Apps are things you interact with and the screen has to update and change to indicate this interaction. The UX designer helps determine what this all looks like

In the case of music apps, this may be:

what happens when the play button is pressed? Obviously the music plays, but what else happens on the screen.
What does the controls look like for the song playing?
How do we indicate what song is playing?
What happens when you scroll down?

This is where a UX designer really nerds out on the details of the app. Sometimes it's a UI designer who is working on this part, but in general UX designers at the very least help design.

when you hit play on Spotify a number of design elements happen:

The play button does a slight animation to indicate it was pressed
Equalizers play alongside the song that is playing to indicate that is the song that is playing
A notification pops up letting you know you can play this song on other speakers

Visual Design

Now get in to the eye candy part of UX design. This is the part that's most fun and gets the most attention. Typically when people think design or UX design they think about the colors, type, gradients, etc.

Well to most people it's the fun part. I still nerd out over the exploration of layouts and interaction design. I feel like the meaty part of problem solving lies there.

But, that's not to say the visual design doesn't help to solve the overall problem of "how do we provide the best user experience?" because it definitely does.

The visual design is what people first notice. It makes the app look cool, interesting, and stand out.

Here, the visual design is partially determined by the brand. Spotify owning green means they'll use green for prominent buttons (like the play button). It would be silly if they made it red.

In similar fashion, Apple uses the red, and Amazon with the lighter blue.

Beyond that, the UX designer - and to a certain extent UI designer - determine the intricacies of the visual design. Things such as spacing, typography, and the overall feel of the page.

Visual Differences in streaming music apps

Motion Design

Motion design is an underrated part of UX design. When done right, it helps to communicate content and information. It's a bit of an offshoot of interaction design. As seen above the equalizer is a good example of motion design. It's the UI moving as a way to communicate.

Back To Problem Solving As A UX Designer

So as you can see, the three different apps took on different approaches to Flow, Layout, Interaction, and Visual design. It goes back to the bigger problem they are solving. It's not simply: "design a music playing app".

A UX designer has to understand the business direction and all the features that go along with it. Spotify clearly has a lot more features it needs and wants to push. There app has more of that embedded into it. Apple Music not so much and it reflects that.

It's why you have different layout and different solutions. Though it seems like similar products on the surface, each UX designer is solving slightly different problems.

A Few Caveats

When I say "UX designer" it can mean on designer, but often means multiple designers

Most apps are a product of teams working together. So while it is the UX designer's responsibility to design the user experience, plenty of inputs come from other roles. Product managers, Marketing, Commercial, Engineering all have inputs the UX designer takes into consideration.
UX designer is a fuzzy term. Sometimes the equivalent is referred to as a product designer.