Developer Interview Q&A

About This Section

Technical interviews are a critical step in landing a developer job. This section covers the most frequently asked questions across web development, CS fundamentals, and general programming — with clear, concise answers to help you prepare confidently.

HTML Interview Questions

• What is the difference between <div> and <span>?
  <div> is a block-level element; <span> is inline. Use div for layout sections, span for styling inline text.
• What is semantic HTML?
  Using HTML elements that convey meaning — like <header>, <nav>, <article>, <footer> — rather than generic divs.
• What is the purpose of the <meta viewport> tag?
  It controls the layout on mobile browsers, enabling responsive design.

CSS Interview Questions

• What is the box model?
  Every element is a box with: content → padding → border → margin from inside out.
• Explain CSS specificity.
  Specificity determines which CSS rule wins when multiple rules target the same element. ID > Class > Tag.
• What is Flexbox and when would you use it?
  A one-dimensional layout model for arranging items in a row or column. Use it for navigation bars, card layouts, and centering content.

JavaScript Interview Questions

• What is the difference between var, let, and const?
  var is function-scoped and hoisted. let and const are block-scoped. const can't be reassigned (but its properties can be mutated).
• What is a closure?
  A function that remembers the variables from its outer scope even after that scope has finished executing.
• What is the event loop?
  JavaScript is single-threaded. The event loop handles asynchronous operations by queuing callbacks and executing them when the call stack is empty.
• What is the difference between == and ===?
  == performs type coercion before comparing. === compares both value and type strictly. Always prefer ===.

CS Fundamentals Questions

• What is the difference between a process and a thread?
  A process has its own memory space; threads share memory within a process. Threads are lighter but require careful synchronization.
• What is Big O notation?
  A way to describe algorithm efficiency. O(n) means time grows linearly with input size. O(1) is constant time regardless of input.
• What is REST?
  Representational State Transfer — an architectural style for building APIs using HTTP methods (GET, POST, PUT, DELETE).

What's Next?

Test your knowledge with Quizzes, or review key syntax with Cheat Sheets.