• UIUX Engineers

Top 10 Interview Questions for UI Developer

  • November 26, 2020
  • Muhammad Ahmad
  • POSTED ON November 26, 2020
  • POSTED BY Muhammad Ahmad

With a UI developer, you have endless possibilities when it comes to designing and developing a website, app, or even software. UI developer interview questions is an attempt to explore the scope of this area and know the market trends to hire the right resource. It is an undeniable fact that you can use powerful

With a UI developer, you have endless possibilities when it comes to designing and developing a website, app, or even software. UI developer interview questions is an attempt to explore the scope of this area and know the market trends to hire the right resource.

It is an undeniable fact that you can use powerful design to make a lasting impact. But, how can you achieve that brilliance? You can kill two birds with one stone, by hiring a Full-stack UI developer. He/she will help you transform those amazing designs into interactive web pages and app slides.

In order to hire the best, you have to make a checklist. Here, you have some top interview questions, that you can use to hire the top industry designers. However, they can also be guidelines for UI developers to understand the demands in the market.

Let’s get started!

Straight from the horse’s mouth

With UI design and development, the future appears to be quite promising. Because UI is everywhere and we need to understand the very basics of it. A simple introduction to a UI Developer is that he is a ‘solution provider’ when it comes to starting the development process, going through it, and even after that. If you need updates or maintenance, a UI developer comes to your rescue.

However, many developers say that a full stack developer having command over front-end development and backend development helps you do multiple tasks. That includes Interactive and Responsive UI designs, Powerful development, and functionalities along with a successful deployment.

  • UI Developer
  • UI/UX Engineer ( Designing + Front-End Coding)
  • Full-Stack Developer ( Designing+ Backend and Front-end Coding + Hosting)
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You need to get UI Developers onboard

It is very crucial to understand that if there is something you need, what is the purpose behind it? It helps you to understand the value addition of that very resource or thing. It can be a strategy and it can be a new resource. The world has come a long way in design, and development solutions running seamlessly on multiple devices. They make it possible for businesses to reach customers.

Your design meets the eye and brings customers to websites. But what makes them stay? Its the interactiveness, responsiveness, and user-friendliness on your websites and online stores. A UI developer makes it possible to visually present that design as an experience to the customer or targeted user.

Take a look at the below technical queries!

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Top 10 Interview Questions for UI Developer

With having access to top UI developer interview questions and answers, you have the leverage to get to know the required skills, familiarize yourself with it. It will allow you to assess the resource based on their expertise, in-demand market skills and to judge the knowledge of the respective candidates.

Take a look at the top interview questions and answers for a UI developer:

Question 1:

How do you create a sticky menu?


You can manually add CSS code to create a sticky menu as well as the plugin method. However, adding the CSS code to your WordPress theme. You can:

  1. Login to your WordPress dashboard
  2. Move to ‘Appearance’ and ‘Customize’
  3. Then click on the “Additional CSS’
  4. Add the Code

CSS Code:

#website-navigation {
margin:0 auto;
border-bottom:1px solid #dadada;
text-align: center;

Once you have added the code, replace the ‘#website navigation’ with the id used for the menu. Moreover, you can publish it by clicking on the blue button that you see. Once you refresh the website, you would be able to see the sticky menu on your website.

The answer doesn’t end here because here comes the tricky part. The sticky menu on the website is not always sticky but the standard menu covert to the sticky menu on any event. For example the scroll event.

window.onscroll = function() {myStickyMenu()};

var navigation= document.getElementById("#website navigation");

var stickyNavigation = navigation.offsetTop;

function myStickyMenu() {
  if (window.pageYOffset >= stickyNavigation ) {
    navbar.classList.add("sticky-navigation ")
  } else {

Question 2:

How do you center align an image without losing the aspect ratio of the image?


You can use two solutions using CSS background property or with the HTML & CSS combined without losing the aspect ratio of the image such as:


#imageHolder {
    width: 400px;
    height: 400px;
    line-height: 400px;
}#imageHolder img {
    max-width: 100%;
    display: inline-block; /* Instead of display: block; */
    margin: 0 auto;
    vertical-align: middle;


<div id="imageHolder">
<img src="image.jpg">

Question 3:

What are the semantic tags in HTML5?


You can use the following semantic tags to differentiate different parts on a web page.


Question 4:

How do you render or compile HTML, CSS, and JS?


HTML is a markup language. i.e, you are just defining how things are displayed to end-users. The CSS is to design the look and feel and JS is a scripting language to make the content dynamic. All these are front end languages and these are rendered by the browser itself. And yes, browsers do contain something similar to a compiler ( called parser) which will identify the various tags and design instruction to display them accordingly.

Question 5:

How do you explain event binding in JS?


Once JavaScript is used on HTML pages, the things that are performed by the user or the browser can be regarded as Events. You can add the event handler for a specific event in order to operate a certain javascript function. Now that’s called event binding.

For example:

  • When HTML web page finishes loading
  • If you click the HTML Button
  • If the input field changes
    <div data-bind="event: { mouseover: enableDetails, mouseout: disableDetails }">
        Mouse over me
    <div data-bind="visible: detailsEnabled">
<script type="text/javascript">
    var viewModel = {
        detailsEnabled: ko.observable(false),
        enableDetails: function() {
        disableDetails: function() {

Question 6:

What is Sass or LESS?


Make Writing CSS simpler with the two most popular CSS preprocessors named LESS and Sass. Designing is made more efficient and easier with these distinctive stylesheets extensions. They are compiled into CSS stylesheets so that the browser can easily read them. You can use nested blocks, variables and so much more. The example is below:

$primary_color: #333;

/* use the variables */
.main-header {
  background-color: $primary_color;

.menu-left {
  background-color: $primary_color;

Question 7:

What are the properties of CSS Flex?


CSS flex property can be denoted as:

  • flex-grow
  • flex-shrink
  • flex-basis

Question 8:

How do you ensure the browser compatibility of your UI?


Each browser handles the frontend languages in their own way. There is a chance if one HTML tag or CSS property works in one browser that it might not work on another browser or previous/newer version of the browser. The new version of the browser code may be deprecated. For this, we have to write browser-specific code or even browser version-specific code. See the CSS example below:

The below code works on chrome, safari, and opera

 >=14.selector:not(*:root) {}

The below code works on chrome

>= 28, safari >= 9and opera >=14 and IE/ME >= 12
@supports (-webkit-appearance:none) {}

The below selector work on Firefox 1.5

1.5 & 2body:last-child .selector, x:-moz-any-link {}

Question 9:

What do you know about ionic/ Bootstrap/ Material design?


Ionic – An open-source library of HTML, CSS, and JS components to build highly interactive and hybrid mobile apps.

Boostrap- A CSS based open source and free framework that contains CSS+ JS templates to develop modern website designs and web apps.

Material Design – A design language developed by Google, that enables you to create highly interactive designs by using grid-based layouts, animations, etc.

Question 10:

How can you increase web page performance?


You can do it with help of :

  • Reduction of image sizes
  • Implementing the Cache
  • Reducing external HTTP Requests
  • Making it mobile-friendly

Piece of Cake – Hire UI Developer

Your guess is as good as mine because you have landed just at the right place and at the right time. Timing and the right team make the best combination to empower you to acquire all your goals. To hire the best people, sometimes you have to cross oceans. Steve Jobs puts it very eloquently:

“The secret to my success is that we’ve gone to exceptional lengths to hire the best people in the world.”

Steve Jobs

The question remains: How can you hire the best UI developers online?


Muhammad Ahmad

Currently serving as the SEO Manager at vteams, Ahmed is a highly skilled individual with several years of experience of Digital Marketing.


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