When you look at a full website, it can feel overwhelming. Buttons, animations, forms, databases, logins, servers—there are so many moving parts. But here’s the good news: developers don’t build everything from scratch.

In fact, most modern websites are built by combining ready-made building blocks called libraries, packages, and frameworks.

What Are Libraries and Packages?

Imagine you’re building a house. You wouldn’t make your own bricks or wires—you’d buy them. It’s the same in coding. A library or package is a reusable piece of code written by someone else that solves a common problem—like showing a calendar, handling logins, or creating animations.

For example, instead of coding a date picker from the ground up, a developer can just install a date picker package, customize it, and plug it into their site.

These packages are often shared through online platforms like npm (Node Package Manager), which is like an app store for code. Developers use npm to install and manage packages in their project.

Using Packages in the Front End

In the front end (what the user sees), developers often use UI libraries to save time and keep the look consistent. Here are a few common examples:

React: A JavaScript library that helps build user interfaces. React breaks everything into small components, like buttons, headers, and menus. Tailwind CSS or Bootstrap: Styling libraries that give pre-designed buttons, layouts, and spacing tools so you don’t have to write all the CSS from scratch. Axios: A package to make HTTP requests (like when your app talks to the backend). React Router: Handles page navigation without reloading the whole site.

If someone wants to build a front-end login form, they might use React for the structure, Tailwind for styling, and Axios to send the login data to the server—all done using existing packages.

Using Packages in the Back End

In the back end (the logic and data), developers also rely on packages and frameworks to speed up development. A few common tools include:

Express.js: A framework for building web servers in Node.js. It handles routes, requests, and responses with very little code. Mongoose: A package for working with MongoDB (a type of database). It helps structure and validate data. jsonwebtoken: A package to handle user login sessions using tokens (so people stay logged in securely). bcrypt: Helps securely hash and compare passwords.

For example, to set up a secure login system, a backend developer might use Express to build the server, bcrypt to hash the password, and jsonwebtoken to manage sessions—all with packages that can be installed in minutes.

Why Use Packages?

Saves Time: Developers don’t have to reinvent the wheel. Tested and Trusted: Popular packages are often used by thousands or millions of developers. They’re battle-tested. Easier Maintenance: If something breaks or needs an update, you just upgrade the package. Focus on What Matters: Developers can spend their time building unique features instead of solving common problems again and again.

How Are Packages Installed and Used?

Most packages are installed using a command line. For example:

npm install react

That command downloads React and adds it to your project. Once it’s installed, you can import and use it in your code:

import React from 'react';

It’s like grabbing a LEGO piece from a toolbox and snapping it into your project.

In Summary

Modern websites are built like LEGO models using pre-built blocks. These blocks come in the form of packages and libraries created by developers around the world. Whether you’re working on the front end or the back end, you don’t have to build everything yourself. By using packages, developers work faster, more securely, and more consistently—focusing their time on the parts of the site that make it unique.