Frontend Developer 路 Intern to senior

Frontend Developer Interview Questions and Answers

Frontend interviews combine language fundamentals (closures, the event loop, async code) with framework knowledge and an understanding of how the browser renders and updates the page.

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93 questions

  • JavaScriptEasy

    What is hoisting in JavaScript?

    Hoisting is JavaScript moving declarations to the top of their scope during compilation, so functions and var variables can be referenced before the line where they are written.

    Intern 路 Junior 路 Functions & Scope
  • ReactEasy

    What is the virtual DOM in React and how does it work?

    The virtual DOM is a lightweight JavaScript copy of the UI that React compares with the previous version after each update, so it only changes the parts of the real DOM that actually differ.

    Intern 路 Junior 路 Performance
  • ReactEasy

    What is the difference between props and state in React?

    Props are read-only inputs passed from a parent component, while state is data a component owns and can change over time, which triggers a re-render when updated.

    Intern 路 Junior 路 State Management
  • HTMLEasy

    What are semantic HTML elements and why do they matter?

    Semantic elements describe their meaning in the name, such as header, nav, main, article and footer, so browsers, assistive technology and search engines can understand the page structure.

    Intern 路 Junior 路 Accessibility
  • CSSEasy

    What is the CSS box model?

    Every element is a box made of content, padding, border and margin. The default content-box size counts only the content; border-box includes padding and border in the width you set.

    Intern 路 Junior 路 CSS Layout
  • CSSEasy

    What is the difference between inline, block and inline-block in CSS?

    Block elements start on a new line and take the full available width; inline elements sit in the text flow and ignore width and height; inline-block sits in the flow but accepts width, height, padding and margin on all sides.

    Intern 路 Junior 路 CSS Layout
  • TypeScriptEasy

    What is TypeScript and why do we use it?

    TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. It catches type errors in the editor and at build time, and it documents the shape of data for the next person who reads the code.

    Intern 路 Junior 路 Types & Type System
  • GitEasy

    What is Git and how is it different from GitHub?

    Git is a distributed version control system that tracks changes to files on your machine; GitHub is a hosting service for Git repositories that adds collaboration features such as pull requests, code review and CI.

    Intern 路 Junior 路 Git
  • GitEasy

    What is the difference between git fetch and git pull?

    git fetch downloads new commits from the remote without changing your working branch; git pull runs a fetch and then merges (or rebases) those commits into your current branch.

    Intern 路 Junior 路 Git
  • Software TestingEasy

    What is the difference between unit, integration and end-to-end tests?

    Unit tests check one small piece of code in isolation, integration tests check that several pieces work together (for example code plus a real database), and end-to-end tests drive the whole application the way a user would.

    Intern 路 Junior 路 Testing
  • JavaScriptEasyCoding

    How do you check if a string is a palindrome in JavaScript?

    Normalise the string (lower case, remove non-alphanumeric characters), then compare characters from both ends moving inward with two pointers. This is O(n) time and O(1) extra space beyond the normalised copy.

    Intern 路 Junior 路 Coding Problems
  • BehavioralEasyBehavioral

    How do you answer "Why should we hire you?" as a developer?

    Connect two or three of your strongest, provable skills directly to the needs in the job description, give a short piece of evidence for each, and show genuine interest in the team鈥檚 work.

    Intern 路 Junior 路 Behavioral Interviews