Gatsby vs Next.JS - What, Why and When?

I am still getting people reading this article nearly two years after writing it - which is awesome! But unfortunately, a lot of what is in this article is out of date.

I wrote a new version of this post updated for 2021. It can be found here --> https://dev.to/jameesy/gatsby-vs-next-js-in-2021-what-why-and-when-2fae

Ok firstly, I digress, I am a massive fan of both of these "frameworks". I can usually be seen gushing about them on my Twitter or Instagram, however, without a doubt, the question I get asked the most when talking about these tools is which is better?

Should I use Next.JS? But I have heard Gatsby is pretty 🔥, maybe I should use that?

So I thought I would discuss it a bit further in-depth and hopefully make the choice a little bit clearer.

LETS FIGHT!

Gatsby & Next - An Introduction

So what are Gatsby and Next other than buzzwords you have heard mentioned before but never really understood?

To put it in the most basic terms, in the same way, create-react-app will create you a boilerplate of a React project, these two frameworks will lay the foundations for you to create an application.

They have separated away from create-react-app however, in the sense that they are not classed as boilerplates, but toolkits, laying the foundations and then giving you a set of instructions on how to build the house as well.

To summarise:

create-react-app - Lays the foundations of a React Project. The rest is up to you.

Gatsby & Next - Lay the foundations of a React Project. Give you guidelines on how you should build on top of them.

...

But huh? That's strange? They both do... the same thing?

Sort of.

At first glance, they both look very similar in the sense they both:

• Provide a boilerplate application.
• Generate incredibly performant, accessible and SEO friendly websites.
• Create Single Page Applications out-of-the-box.
• Have a really awesome developer experience.

But actually, they are fundamentally different.

Server Side Rendered vs Statically Generated

Ok, so we start to get a little bit technical here, so stay with me... It's not too bad!

Gatsby is a static site generator tool. A static site generator generates static HTML on build time. It doesn’t use a server.

Next.JS is mainly a tool for server-side rendered pages. It dynamically generates the HTML every time a new request comes in with the use of a server.

Of course, both can call APIs client side. The fundamental difference is Next requires a server to be able to run. Gatsby can function without any server at all.

Gatsby just generates pure HTML/CSS/JS at build time, whereas Next creates HTML/CSS/JS at run time. So each time a new request comes in, it creates a new HTML page from the server.

I'm not going to go too deep into the pro's and cons of each here, however for some more in-depth reading check out this post - https://dev.to/stereobooster/server-side-rendering-or-ssr-what-is-it-for-and-when-to-use-it-2cpg

Data Handling

Another fundamental difference between the tools is the way in which they handle data.

Gatsby tells you how you should handle data in your app.

Next leaves the decision entirely up to you.

What does that even mean?

Gatsby uses something called GraphQL. GraphQL is a query language and if you’re familiar with SQL, it works in a very similar way. Using a special syntax, you describe the data you want in your component and then that data is given to you.

Gatsby makes that data available in the browser when needed by your components.

An example:

import React from "react"
import { graphql } from "gatsby"
export default ({ data }) => (
  <div>
    <h1>About {data.site.siteMetadata.title}</h1>
    <p>We're a very cool website you should return to often.</p>
  </div>
)
export const query = graphql`
  query {
    site {
      siteMetadata {
        title
      }
    }
  }
`

In the above example, you can see that we have a query to fetch title and then display title within the component. Awesome!

Gatsby also has lots of plugins for various data sources which (in theory) makes it easy to integrate against many data sources. Some examples of data sources plugins are Contentful, Wordpress, MongoDB and Forestry. This allows you to do things such as hook your site up to a CMS and have external control of the content.

When building for production, GraphQL is no longer used, but the data is persisted into JSON files instead.

... Ok cool.

Next on the other hand, how you manage your data is completely up to you. You have to decide on your own architecture how to manage data.

The benefit of that is that you aren't tied into any tech that you may or may not want to be using.

So what should I choose?

Whether you should use Gatsby or Next depends very much on your use case, as really they are both awesome.

When To Use Next.JS

If you have lots of content or if you expect your content to grow a lot over time, then static generated web pages are not the best solution for you. The reason is that it takes much time to build the site if you have lots of content.

When creating a very large app with thousands of pages it can be fairly slow to rebuild. And if you have to wait for a chunk of time when you hit publish before it goes live it’s not a perfect solution.

So if you have a site with content that you will expect to grow and grow over time, then Next.JS is the best choice for you.

Also, if you want more freedom with how you access your data, Next.JS is worth a shout.

It's worth mentioning here that the documentation for Next is some of the best I have ever come across. It has an interactive introduction that quizzes you as you go through the content to make sure you are following along :) awesome! 👏

When to Use Gatsby

I tend to, and this is my personal preference, use Gatsby when I am building small-scale websites and blogs. The eco-system is perfect for hooking up to a CMS (it is literally a breeze) and there are some awesome guides on how to get going with it all.

It is (in my mind) easier to get up and running with Gatsby, so that is worth keeping in mind. Again, the documentation is to a really high level, packed full of tutorials for you to follow along.

Gatsby also comes with some "starter" templates, as well as a relatively recently introduced "themes" which all make getting a fully functioning web app up and running a quick process.