What is Gatsby?

Gatsby is a free, open source static site generator that harnesses React. Static site generators are software applications that create static pages from a template or component and supplement them with content from a source. Static site generators are an alternative to a more traditional database-driven CMS, such as WordPress. In these conventional systems, content is managed and stored in a database. When the server receives a particular URL request, the server retrieves data from the database, mixes it with a template file, and generates an HTML page as its response. Generating HTML on demand can be a time-consuming process and can leave the user twiddling their thumbs or, worse, leaving your site. Bounce rates (the percentage of visitors to a particular website who navigate away from the site after viewing only one page) hover below 10% for websites that take less than 3 seconds to load, but the number jumps to 24% for a 4-second load time and 38% for a 5-second load time.

Static site generators like Gatsby, on the other hand, generate pages during a build process. During this process, Gatsby brings in data to its GraphQL layer, where it can be queried in pages and templates. The requested data is then stored in JSON and accessed by the built pages, which are composed of HTML, JS, and CSS files. A user can deploy these generated pages to a server. When it receives a request, the server responds with predetermined, static, rendered HTML. As these static pages are generated at build time, they eliminate the latency that databases would introduce. You can even do away with web servers altogether and have your site served via a CDN pointing to a storage medium, such as an AWS Simple Storage Service (S3) bucket. The difference is striking; web experiences built with Gatsby are lightning fast, as nothing can be faster than sending static content.

Important Note

A static site can contain dynamic and exciting experiences! It is a common misconception that "static" means the site is stationary. This could not be further from the truth. The word "static" only refers to the manner in which files are retrieved by a client.

While Gatsby is known for static site generation, recent versions also include server-side and deferred static generation, rendering functionality for when static generation is not enough.

Aside from creating a blazing-fast user experience, Gatsby also has a focus on developer experience. As we learn and build, I'm sure you will start to recognize how easy it is to use. The way it achieves this can be broken down into four steps.

Community

Gatsby has an incredibly supportive community backing. At the time of writing, over 3,600 people have contributed to the Gatsby repository. This is further amplified by the plugin ecosystem surrounding Gatsby; the community has created more than 2,000+ plugins that abstract complex functionality that other developers may wish to use in their own projects. These plugins are distributed as packages stored on a JS repository, such as NPM, that can be added to your project in a few lines. They can extend your site by sourcing content, transforming data, creating pages, or theming your application.

Sourcing content from anywhere

Every day, the amount of data we need to combine to create experiences is rising. In traditional React applications, managing multiple sources of data could become a nightmare. Storing, massaging, merging, and querying data all require complex solutions that struggle to scale.

Gatsby does this differently. Whether you are sourcing data from a CMS, real-time database, or even a custom Application Programming Interface (API), you can merge all of this data into a unified data layer. The Gatsby community is constantly contributing source plugins to allow you to ingest data from your favorite sources with ease. Nine times out of ten, you won't need to write a single line of code to source your data, but for the times when you do, we will be covering plugin creation in Chapter 10, Creating Gatsby Plugins.

Once ingested into this data layer, we can explore and query all our sources of data in one place using a uniform data layer. Using the power of GraphQL, we can query our data in the same way when rendering pages regardless of their source. The GraphQL layer is transitory and doesn't exist after the application has been built, so doesn't affect the size of your production site. If GraphQL is something new to you, don't worry – I will be explaining how it works in Chapter 3, Sourcing and Querying Data (from Anywhere!).

Building tooling you already know

Often when we approach new technologies, we are faced with a steep learning curve as we understand new syntax and ways of thinking. In Gatsby, we build on your existing knowledge of React instead of starting from scratch. Underpinning all of our code is the same React component model many of you already know. You should feel pretty confident from the beginning, as the code should look familiar, and if you're not, Gatsby can also help you learn React from a more "content-driven" approach.

Supercharging web performance

As web developers, we can spend considerable time tinkering with websites to squeeze every ounce out of their performance. Sometimes, this can take as long, if not longer, than building the design. Also, performance gains can sometimes be undone instantly by a change to the site design outside of your control. It's because of this that some large organizations have dedicated teams to improve site performance. But it doesn't have to be this way! As we start to build together, you will see that load times go from seconds to milliseconds, and your site will feel far more responsive than a conventional React app. Gatsby has plenty of tricks up its sleeve that improve performance, some of which we will touch on at the end of this chapter. It also turns your site into a Progressive Web App (PWA) with just a few lines of code – if that's not cool, I don't know what is!

Important Note

An essential distinction between Gatsby and React is that Gatsby is a "framework," not a "library." When using a library, you control your application flow; you call it when you need it. When using a framework, however, there is an inversion of control. Frameworks command that you adhere to a particular flow and layout defined by them. Working within a framework can often be seen as a benefit, as any developer familiar with the framework will know where to find relevant files and code.

I hope you are beginning to see some of the great reasons why Gatsby is such a powerful tool. Let's now see it in action.