Up to this point, we’ve mainly focused on developing an application that can be executed locally on a computer. To use an application like this, users would have to download it and possibly install it on their system. Likewise, as developers, we’ll have to create a release that they can install, and we may have to make sure that the release is compatible with various different operating systems and computer architectures.

For decades, this was really the state of the art of computer programming. However, starting in the 2000s, things began to drastically change with the rise of Web 2.0 and interactive website. Soon, a whole new type of application, the web application, became commonplace.

Today, outside of video games and a few specialized applications, many computer users primarily interact with web applications instead of applications installed locally on their computer. Some great examples are the various social media sites such as Facebook and YouTube, productivity tools such as Microsoft Office 365 or Google Drive, and even communication platforms such as Slack and Discord.

To make things even more complicated, many of those web applications include versions that you can install and run locally on your computer or smartphone, but in many cases they are simply a lightweight wrapper around the web application. In that way, it appears to be running as a local application, but it is really just a version of the same web application that is stored locally.

In this chapter, we’re going to pivot our focus to building a web application. To do that, we’ll have to introduce many new concepts to lay the foundation for working in the web, so there will be lots of new content and ideas in this chapter.

Some key terms that we’ll cover:

• Hypertext Markup Language (HTML)
• HTML Tags
• Cascading Style Sheets (CSS)
• CSS Selectors
• JavaScript (JS)
• Hypertext Transfer Protocol (HTTP)
• Static Web Servers, such as Apache, IIS, and nginx
• Dynamic Web Pages
• Templates
• Template Rendering
• Web Frameworks, such as Spring (Java) and Flask (Python)
• Web Requests
• Web Responses
• Routing
• Uniform Resource Locator (URL) and Uniform Resource Identifier (URI)

At the end of this chapter, you’ll be able to generate your own data driven web pages using a web framework and its built-in templating engine!