What is Node.js

Node.js is a JavaScript runtime that runs outside the browser. It lets you use JavaScript to build server applications, command-line tools, and more.

Key differences between browser JavaScript and Node.js:

Browser JavaScript:

  • Runs in the user’s browser
  • Has access to browser APIs (DOM, localStorage, fetch)
  • Can’t access the file system
  • Can’t make direct database connections
  • Limited by browser security restrictions

Node.js JavaScript:

  • Runs on the server computer
  • Has access to server APIs (file system, databases, network)
  • Can read and write files
  • Can connect to databases directly
  • Can handle multiple requests simultaneously

Browser JS v Node.js

Why Node.js for Backend?

  • Same language - You already know JavaScript or TypeScript
  • Fast and efficient - Great for handling many requests
  • Huge ecosystem - Millions of packages available via npm
  • Active community - Lots of resources and help available

Node.js vs Other Backend Languages

While you could use Python, Java, or other languages, Node.js is popular because:

  • JavaScript everywhere - Same language for frontend and backend
  • Fast development - Less context switching
  • Rich ecosystem - npm has packages for almost everything
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