Frontend Interview Handbook3 min read

What does a frontend engineer do?

Front-end engineers, also known as front-end developers, create the visual elements of an app or website. They design the user-facing content that users see and interact with. That is what a frontend developer does day to day, and MDN’s Learn web development curriculum covers the core skills.

They’re the ones behind the layout of a landing page, the feel of a button when you hover over it, and how smoothly a mobile nav menu slides open. Their work is where code meets design. It’s about making things look good, feel good, and work.

Do you need a degree in computer science?

Not at all.

Many frontend engineers come from traditional computer science backgrounds, but just as many do not. Some started in design, others in teaching, marketing, or completely unrelated fields. Many of them either taught themselves or acquired skills through coding boot camps.

The one thing they all have in common is this: they built projects. They got their hands dirty. In frontend, what matters is your ability to ship clean, usable interfaces, not where you went to school.

The Core Tools a Frontend Developer Uses

Most frontend engineers today work with React, a JavaScript framework that enables the easy development of fast and interactive web applications. It is especially common at more prominent tech companies.

But not everyone uses React. At smaller companies or in older codebases, you might run into Angular, jQuery, or even plain HTML, CSS, and JavaScript.

That’s why the fundamental foundation for any frontend engineer is what I call the three sacred tools:

HTML for structure
CSS for styling
JavaScript for interactivity

Frameworks come and go. These three never change.

What are the differences between the frontend and the backend?

Frontend Engineer	Common Skills	Backend Engineer
Builds user interfaces with HTML, CSS, JavaScript, and React	Writes clean, maintainable, and testable code	Builds scalable APIs and services using Node.js, Go, Java, or Python
Focuses on responsive design and performance	Understands computer science fundamentals (DS & Algos)	Optimizes database queries and system performance
Implements animations, state management, and accessibility	Uses Git and CI/CD pipelines	Handles authentication, authorization, and data security
Works closely with design and product teams	Participates in code reviews and architecture discussions	Integrates third-party APIs and manages cloud services
Uses browser dev tools and performance profiling	Follows Agile or Scrum development processes	Monitors and logs backend errors and metrics

Frontend engineers build everything the user sees and touches. Backend engineers build what powers all of that behind the scenes.

A frontend engineer might build the form. A backend engineer handles what happens after you submit it.

Frontend is about layout, responsiveness, polish, and design systems. Backend is about databases, APIs, infrastructure, and data flow.

They both require strong problem-solving skills, but the flavor of those problems is different. Frontend is about the user experience. Backend is about what happens under the hood.

Is frontend engineering right for you?

If you’ve got a creative eye and enjoy design as much as development, frontend might be your sweet spot.

Frontend is an excellent fit for people who care about visual detail and want to build things that users see. It’s the part of software engineering where creativity and logic go hand in hand.