There’s no denying that JavaScript is everywhere, but just how are some of the world’s largest tech companies using JavaScript? For these 10 companies, JavaScript is immensely important, and that doesn’t look like it’s going to change any time soon.

Microsoft

Microsoft

Okay, so you’re probably not going to find JavaScript powering Windows anytime soon, but Microsoft relies on JavaScript for a whole lot else.

First off, Microsoft needs to work closely with JavaScript to built its Edge web browser. All browsers need to process and execute JavaScript efficiently, so Microsoft has developed and maintains its own JavaScript engine for Edge. Actually, there has been talk of them creating an alternate version of NodeJS with the Edge engine.

Recently, Microsoft has really embraced NodeJS. They thoroughly support Node on the Azure cloud platform. Its one of Azure’s major features, and they’ve integrated Visual Studio support for Node.

Microsoft has also developed a version of Node for Internet Of Things(IoT) applications. NodeJS is great of IoT because it’s light weight and efficient.

PayPal

PayPal

PayPal has obviously been using JavaScript on the front end of their website for a long time, but that’s only the beginning.

The online payment giant was one of the earliest adopters of NodeJS. During an overhaul of their account overview page, they decided to try building the page in Node at the same time as their usual Java development. The NodeJS version worked out so well, that they chose to use it in production and build all client-facing applications in Node going forward. That means that most of what you see in your account is running on Node.

PayPal even went as far as to create and maintain their own version of Express, called KrakenJS. It’s pretty obvious that they like JavaScript over at PayPal.

Netflix

Netflix

Like PayPal, Netflix started out using Java for just about everything. They too ran into problems with Java’s size and the time it required to develop.

Over time, Netflix moved away from its more traditional structure into the cloud and started to introduce NodeJS. With Node, Netflix was able to break down pieces of their user interface into individual services. This more distributed approach was able to speed things up an alleviate stress on their servers. Today, a large portion of Netflix’s interface is running on Node.

Groupon

Groupon

Groupon used to be infamously slow. Why? They were powered by Ruby on Rails. That’s the same framework that brought you the Twitter fail whale.

Groupon was all one gigantic Ruby on Rails application. Thanks to difficulties in speed and maintainability, they decided to change over to NodeJS. Node allowed Groupon to rebuild their entire US website by breaking down everything into individual NodeJS web applications. Now, Groupon is made up of over 20 Node applications, and it moves much faster as a whole.

Groupon is currently moving all of their international sites to NodeJS and has joined the NodeJS Foundation. It’s pretty clear that they are happy with their change.

Uber

Uber

Uber needs to handle loads of data in real time. They have millions of requests coming in continuously, and that’s not just hits on a page. Uber needs to track driver locations, rider locations, and incoming ride requests. It has to seamlessly sort that data and match riders as fast as possible.

All of that plays to NodeJS’s and JavaScript’s strengths. Node is designed to handle requests and hand off data quickly. It’s asynchronous capabilities are a huge part of that. Node is central to Uber’s user facing stack for just that reason.

Facebook

Facebook

You’re probably aware that Facebook uses JavaScript. It’s kind of hard to miss. What’s probably not as obvious is exactly how much JavaScript goes into making Facebook and how much Facebook is involved in JavaScript development.

Try disabling JavaScript in your web browser and going to Facebook. The website will actually stop you from logging in because it won’t work without JavaScript.

You may have noticed the way that Facebook loads. Each piece of the page is separate. Facebook has invented its own way of breaking down and delivering sections of JavaScript separately. In an odd way, each section of your Facebook page is a collection of independent JavaScript applications.

It doesn’t stop there. Facebook created React, one of the most popular front end frameworks. Facebook uses React on Facebook.com as well as Instagram and WhatsApp.

Google

Google

How doesn’t Google use JavaScript? Seriously, it’s everywhere. Google’s search results that spring up as your typing get there with JavaScript. The Gmail web client is powered by JavaScript. Google Docs? Yeah, that’s JavaScript too.

Google develops and usually open sources it’s own JavaScript tools. The most obvious example is AngularJS. Angular is used most prominently in Google’s DoubleClick advertising platform, but it’s also one of the most popular front end frameworks available. It’s even part of the MEAN stack.

Google’s more intensive services, like Google Docs, use Closure Tools. This set of tools compiles JavaScript into a lower-level faster form more suited for rich and highly responsive web applications.

There’s another big point to touch on. Google developed Chrome. Chrome, being a web browser, needed a JavaScript engine, so Google also made V8. V8 not only powers Chrome, it’s at the heart of NodeJS. So, without Google, there would be no Node.

eBay

eBay

eBay’s story is a lot like Netflix’s. For a long time, just about everything in eBay’s tech stack was based on Java. A few years ago, eBay encountered a problem that Java wasn’t the right solution for. They decided to give NodeJS a shot instead.

Node worked so well that eBay not only kept using it for that particular service, they began migrating their entire user facing stack to NodeJS. Now, just about everything that you interact with on eBay is powered by Node. Sure, beneath Node, Java is still dealing with their databases, but eBay still places a lot of trust in NodeJS.

Walmart

Walmart

Most people probably don’t think of Walmart as a tech company, but because they’re one of the largest retailers in the world, their online retail business is gigantic. It’s not much of a stretch to see how they need build a technologically advanced web application do drive their online business.

Walmart started out with Java. It’s a solid enterprise-grade platform that has been the de facto choice for years. However, Walmart needed something faster and lighter weight for their mobile site. So, they turned to NodeJS.

Once again, Walmart began to see Node as a valid Java replacement in loads of other places. Today, the Walmart.com that you see is powered by Node. NodeJS was also the ideal choice for other web applications within their marketplace that require multiple users to be able to access management interfaces simultaneously.

LinkedIn

LinkedIn

LinkedIn relies on NodeJS for its mobile site. A few years back, LinkedIn used Rails for its mobile site. As with other other large Rails applications, it was slow, monolithic, and it scaled poorly.

LinkedIn switched over to NodeJS to solve its scaling problems. Node’s asynchronous capabilities allowed the LinkedIn mobile site to perform more quickly than before while using fewer resources. Node also made data sharing and building APIs easier for the LinkedIn developers.

JavaScript Is Everywhere!

These are only 10 examples, but you can certainly find more. So much of the web runs on JavaScript, it’d be much harder to find a company that doesn’t use JavaScript in some way.

These companies are among the largest tech companies in the world. Many are also running the largest production deployments of NodeJS. The others are responsible for important parts of the JavaScript ecosystem as a whole.

Many of the JavaScript tools discussed in this article are taught here at Ironhack, including NodeJS and the MEAN stack.