17 React Interview Questions You Must Know as a Developer in 2025

React is one of the most in-demand skills for Frontend Developers in 2025. If you’re preparing for a React developer interview in 2025, it’s crucial to stay ahead of the curve with the latest best practices, patterns, and concepts.

This article compiles a list of 17 React interview questions that cover everything from core React principles to advanced performance optimizations that will help you ace your next React developer interview.

Let’s dive in!

1. What is the React Virtual DOM? How is it different from the real DOM & Shadow DOM?

Virtual DOM is a concept where a virtual representation of the real DOM is kept inside the memory and is synced with the actual DOM by a library such as ReactDOM only when necessary.

The Virtual DOM is an object that represents the real DOM in the memory. Since DOM updates are an integral part of any web app but are the costliest operation in frontend development, the Virtual DOM is utilized to check for parts of the app that need to be updated & update only those parts, thus…