CodeSubmit Interview Series

12 Best Frontend Interview Questions in 2023

Want to hire a frontend developer? If so, you need the right frontend interview questions. Here are 12 questions you can use to interview your candidates. Read on!

Frontend interviews

Frontend web development uses HTML, CSS, and JavaScript to develop the graphical user interface of a website so that users can view and interact with it. Several tools, such as Joomla, WordPress, and Drupal, can be used to develop the front end of a website. 

So, frontend developers need to have a good understanding of various tools and platforms. How do you find the right frontend developer? Use these frontend interview questions with answers to assess them. 

Beginner frontend interview questions

What are some great interview questions for junior frontend developers? Use these frontend interview questions for freshers who might not yet have strong technical knowledge, but who understand the benefits of frontend development and what they can bring to your organization. 

1. What skills does a frontend developer need?


A great frontend developer needs to know HTML, CSS, JQuery, and JavaScript. 

They also need to know a Content Management System (CMS) like WordPress, Joomla, or Drupal, cross-browser testing, OOPS, PHP, UX, and SEO. Other beneficial skills are Adobe Photoshop and Angular.

(Note that the ideal answer depends on your requirements. If you use a CMS like Ghost, then you’ll want your candidates to know that CMS.)

2. How do you make sure that your web application or design is user-friendly?


UX is an important frontend development skill (unless you have a UX on your team who can work together with the frontend developer -- either way, your ideal candidate should have at least a basic understanding of UX). 

In your candidates’ answers, look out for what their experience is in terms of implementing usability and accessibility standards. What is their process? 

3. What are your favorite features of HTML5? How have you used them in your previous projects?


Frontend developers frequently use HTML5 for web designs and if they understand how to use it fully, they can save development time and improve the application. In their answers, look out for an understanding and experience of using key features, such as semantic elements, form elements, and tags. (Define what elements your ideal candidate needs to know before the interviews; this will largely depend on your development needs.) 

4. What are some basic design elements?


Basic frontend design elements include:

  • Shape: A shape is a geometric or organic defined area (such as squares, circles, or free-formed shapes). 

  • Line: Linear marks that are created when two shapes meet. 

  • Size: Relationship of the area of one shape in relation to another. 

  • Texture: Surface quality of a shape; smooth, soft, hard, glossy, and so on.

  • Direction: Every line has a direction. There are three directions, vertical, horizontal, or oblique. Vertical creates balance and formality, horizontal offers calmness and stability and oblique gives movement and action.

  • Color: Light reflected off objects. Colors have three main characteristics; a color’s name (blue, green, and so on), value (lightness or darkness), and intensity (brightness or dullness). 

5. How do you structure your source code? 


Frontend developers need to know how to write clear source code. How do your candidates use common standards and how do they explain their use of code organization and comments? How do they use notes to explain the steps they’ve taken? 

Advanced frontend interview questions

What are some advanced frontend interview questions? Here are the best frontend developer interview questions for experienced developers. Remember to focus on the skills that matter most to your team rather than trying to cover it all.

6. What are some of the best ways to increase page performance?


Ways to improve page performance include:

  • Reducing external HTTP requests and scripts 

  • Using compressed and smaller images 

  • Deferring JavaScript to the bottom of the page

  • Cleaning up HTML 

  • Using the latest version of code (eg. PHP)

  • Using caching and CDN

  • Minifying HTML, CSS, and JavaScript

  • Leveraging browser caching

  • GZip and Brotli compress content 

7. What is webpack?


Webpack is a build tool, which puts assets, such as JavaScript, fonts, images, and CSS, in a dependency graph. You can point to local files, like images, and decide how they’re processed in your final JavaScript bundle by using require() in your source code.  

8. What’s the difference between end-to-end tests and unit tests?


End-to-end tests and unit tests have a lot of overlap. End-to-end tests test the website itself instead of the code to ensure that the site behaves as it should. Unit testing, on the other hand, means testing your actual code to make sure functions return expected results for given inputs. 

9. What is the difference between NoSQL and SQL databases?


NoSQL databases (DynamoDB and MongoDB) have dynamic schemas and are non-relational. SQL databases (MySQL, PostgreSQL, and so on) are relational databases with a structured query language. 

10. What is functional programming in JavaScript?


Functional programming uses pure functions, including map, filter, and reduce. Another key concept is immutability. 

11. What is Ajax?


AJAX stands for Asynchronous JavaScript and XML. It allows applications to transport data to and from a server asynchronously without refreshing the page so that a page can be updated without the entire page reloading. 

12. How do you fix browser-specific style incompatibility?


The simplest way to fix this is to utilize a conditional statement in the head tag of your HTML. This enables you to recognize the browser and load an external stylesheet.

Over to you!

There you have it! Now you know how these frontend interview questions can help you identify the right candidate in your interviews. What it comes down to is that you focus not only on their technical skills, but also how they communicate their answers.

Now, interviews are only one part of your hiring process. Another is developer skill assessments. 

If you want to incorporate effective skill assessment tests into your hiring process, try CodeSubmit. We offer a library of proven tests or you can upload your own. We also support 60+ languages and frameworks, including frontend skill tests.

Want to learn more? 

Try CodeSubmit for free. (No credit card required.)