The internet, the web, and the browser

Phase 2 begins with a question that this entire module will answer: what happens when you type an address into a browser and press Enter?

By the end of Module 4, you will be able to trace that journey step by step: from your device, across the internet, to another computer, and back again.

Before following that journey, you need to understand a distinction that people often blur. The internet and the web are not the same thing.

What is the internet?

The internetConcept · lights on your mapinternetThe worldwide network infrastructure (cables, routers, data centers, and shared protocols) that connects computer networks. Not the same as the web, which is only one system running on it. Email and video calls use the internet without being the web. is a worldwide system of connected computer networks.

It includes physical infrastructure such as cables, routers, data centers, cell towers, and networking equipment, and some of those cables run beneath oceans and connect entire continents.

The internet also depends on shared technical rules called protocols, which allow devices and networks built by different companies to exchange information in predictable ways.

A useful analogy is to think of the internet as a massive transportation system where the cables and wireless connections are the roads, routers help direct traffic toward its destination, and protocols are the shared traffic rules that allow everything to move together. Roads, routers, rules.

The internet provides the underlying connections through which information can travel.

What is the web?

The webConcept · lights on your mapwebOne system built on the internet: websites, webpages, links, and web apps reached through a browser. Not the same as the internet, which is the underlying network the web merely runs on., formally called the World Wide Web, is one system that uses the internet, consisting of websites, webpages, links, and web applications that people commonly access through browsers.

In the transportation analogy, the internet is the road system, while the web is one kind of activity taking place on those roads.

The internet existed before the web, and when the web was created, it used the internet’s existing connections to allow people to access linked documents and pages from remote computers.

Today, the web includes much more than simple documents. It contains interactive products such as Google Docs, online banking, social networks, and streaming platforms.

Not everything on the internet is the web

Many other forms of communication also use the internet.

Examples include:

• Email
• Video calls
• Online games
• File transfers
• Mobile-app activity
• Smart-device communication
• Messages sent between software systems

When you use a mobile app to request a ride, the app communicates with remote systems through the internet, and while you are not necessarily visiting a webpage, the app still depends on internet connectivity.

Similarly, a smart television can stream a film through the internet without the user opening a traditional website in a browser. No browser, still the internet.

Some of these products may still use technologies associated with the web behind the scenes. But the important distinction is that the internet is the broader network, while the web is one way of accessing and organizing information through it.

A useful rule is: the web uses the internet, but the internet contains much more than the web.

Why the distinction matters

The difference helps explain common product conversations.

When a company says that it offers both a web app and a mobile app, those are two different user-facing applications, but they may communicate through the same internet and connect to many of the same remote systems.

A web app runs through a browser, while a mobile app runs as software installed on a phone. Their interfaces and capabilities may differ, but both can send information across the internet.

This distinction will become more concrete when you learn about clients, servers, and application architecture.

What is a browser?

A browserConcept · lights on your mapbrowserThe application that retrieves, displays, and runs web content (Chrome, Safari, Edge, Firefox). It interprets HTML and CSS, runs JavaScript, and enforces security restrictions. A powerful runtime environment for web applications, running on top of the device’s operating system. is an application designed to retrieve, display, and interact with content from the web.

Common browsers include:

• Google Chrome
• Apple Safari
• Microsoft Edge
• Mozilla Firefox

When you visit a webpage, the browser contacts a remote system and requests the necessary content, then interprets that content and displays the page on your screen.

A browser commonly works with three core web technologies:

• HTML describes the structure and content of the page.
• CSS controls much of its appearance.
• JavaScript adds behavior and interactivity.

You will explore these technologies more closely later in the module.

The browser does more than display pages

Modern browsers can run sophisticated applications.

Google Docs, for example, operates inside a browser but behaves like a full productivity tool, letting you type, edit, save, collaborate, and respond to changes made by other users.

To support experiences like this, a browser does more than display text and images. It can:

• Run JavaScript
• Store some information locally
• Respond to keyboard, mouse, and touch input
• Play audio and video
• Communicate with remote systems
• Enforce security restrictions
• Keep different websites separated from one another

This makes the browser a powerful runtime environment for web applications.

It resembles an operating system in the limited sense that it manages running web code and controls what that code is allowed to access. But the browser still runs as an application on top of the device’s actual operating system.

Why browsers restrict web code

When you open a website, you are allowing code created by someone else to run inside your browser.

That code should not be able to freely search your computer, read files from unrelated applications, or control every part of your device.

Browsers therefore place web applications inside restricted environments, allowing useful capabilities while limiting access to sensitive parts of the machine.

For example, a website may ask for permission to use your camera or location, and the browser helps enforce that permission instead of allowing the website unrestricted access.

This is another example of abstraction and controlled boundaries. The browser gives web applications a consistent environment while protecting the device underneath.

Connecting the concepts

You can now begin tracing what happens when you visit a website.

Your browser is the local application through which you access the web, and the web is the system of pages and applications you are attempting to reach. The internet provides the connections that allow your browser to communicate with remote machines.

In simple terms: the browser uses the internet to access the web.

Each concept plays a different role:

• The internet is the underlying network.
• The web is a system of linked content and applications that uses that network.
• The browser is the application you use to access and run web experiences.

The mental model to remember

The internet is the worldwide network infrastructure that connects computer networks and allows information to travel.

The web is one system built on the internet, consisting of websites, webpages, links, and web applications.

A browser is an application that retrieves, displays, and runs web content.

All web activity uses the internet, but not all internet activity belongs to the web.

You should now be able to explain why using the internet and browsing the web are related but not identical activities.