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Why and How We Migrated Babylon.js to Azure

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You’re working for a startup. Suddenly that hard year of coding is paying off—with success comes more growth and demand for your web app to scale.

In this tutorial, I want to humbly use one of our more recent “success stories” around our WebGL open-source gaming framework, Babylon.js, and its website. We’ve been excited to see so many web gaming devs try it out. But to keep up with the demand, we knew we needed a new web hosting solution. 

While this tutorial focuses on Microsoft Azure, many of the concepts apply to various solutions you might prefer. We’re also going to see the various optimizations we’ve put in place to limit as much as possible the output bandwidth from our servers to your browser.


Babylon.js is a personal project we’ve been working on for over a year now. As it’s a personal project (i.e. our time and money), we’ve hosted the website, textures and 3D scenes on a relatively cheap hosting solution using a small, dedicated Windows/IIS machine. The project started in France, but was quickly on the radar of several 3D and web specialists around the globe as well as some gaming studios. We were happy about the community’s feedback, but the traffic was manageable!

For instance, between February 2014 and April 2014, we had an average of 7K+ users/month with an average of 16K+ pages viewed/month. Some of the events we’ve been speaking at have generated some interesting peaks:

Spikes in user dataSpikes in user dataSpikes in user data

But the experience on the website was still good enough. Loading our scenes wasn’t done at stellar speed, but users weren’t complaining that much.

However, recently, a cool guy decided to share our work on Hacker News. We were really happy for such news! But look at what happened to the site’s connections:

Big spike in usersBig spike in usersBig spike in users

Game over for our little server! It slowly stopped working, and the experience for our users was really bad. The IIS server was spending its time serving large static assets and images, and the CPU usage was too high. As we were about to launch the Assassin’s Creed Pirates WebGL experience project running on Babylon.js, it was time to switch to a more scalable professional hosting by using a cloud solution.

But before reviewing our hosting choices, let’s briefly talk about the specifics of our engine and website:

  1. Everything is static on our website. We currently don’t have any server-side code running.
  2. Our scenes (.babylon JSON files) and textures (.png or .jpeg) files could be very big (up to 100 MB). This means that we absolutely needed to activate gzip compression on our .babylon scene files. Indeed, in our case, the pricing is going to be indexed a lot on the outgoing bandwidth.
  3. Drawing into the WebGL canvas needs special security checks. You can’t load our scenes and textures from another server without CORS enabled, for instance.

Credits: I’d like to special thank Benjamin Talmard, one of our French Azure Technical Evangelist who helped us move to Azure.

1. Moving to Azure Web Sites & the Autoscale Service

As we’d like to spend most of our time writing code and features for our engine, we don’t want to lose time on the plumbing. That’s why we immediately decided to choose a PaaS approach and not an IaaS one.

Moreover, we liked Visual Studio integration with Azure. I can do almost everything from my favorite IDE. And even if Babylon.js is hosted on GitHub, we’re using Visual Studio 2013, TypeScript and Visual Studio Online to code our engine. As a note for your project, you can get Visual Studio Community and an Azure Trial for free.

Moving to Azure took me approximately five minutes:

  1. I created a new Web Site in the admin page: (could be done inside VS too).  
  2. I took the right changeset from our source code repository matching the version that was currently online.
  3. I right-clicked the Web project in the Visual Studio Solution Explorer.
Visual Studio Solution ExplorerVisual Studio Solution ExplorerVisual Studio Solution Explorer

Now here comes the awesomeness of the tooling. As I was logged into VS using the Microsoft Account bound to my Azure subscription, the wizard let me simply choose the web site on which I’d like to deploy.

Choose Web Site to deployChoose Web Site to deployChoose Web Site to deploy

No need to worry about complex authentication, connection string or whatever.

Next, Next, Next & Publish” and a couple of minutes later, at the end of the uploading process of all our assets and files, the web site was up and running!

On the configuration side, we wanted to benefit from the cool autoscale service. It would have helped a lot in our previous Hacker News scenario.

First, your instance has be configured in Standard mode in the Scale tab.

web hosting plan mode selectionweb hosting plan mode selectionweb hosting plan mode selection

Then, you can choose up to how many instances you’d like to automatically scale, in which CPU conditions, and also on which scheduled times. 

In our case, we’ve decided to use up to three small instances (1 core, 1.75 GB memory) and to auto-spawn a new instance if the CPU goes over 80% of its utilization. We will remove one instance if the CPU drops under 60%. The autoscaling mechanism is always on in our case—we haven’t set specific scheduled times.

Size and scale settingsSize and scale settingsSize and scale settings

The idea is really to only pay for what you need during specific timeframes and loads. I love the concept. With that, we would have been able to handle previous peaks by doing nothing thanks to this Azure service!

You've also got a quick view on the autoscaling history via the purple chart. In our case, since we’ve moved to Azure, we never went over one instance up to now. And we’re going to see below how to minimize the risk of falling into an autoscaling.

To conclude on the web site configuration, we wanted to enable automatic gzip compression on our specific 3D engine resources (.babylon and .babylonmeshdata files). This was critical to us as it could save up to 3x the bandwidth and thus… the price.

Web Sites are running on IIS. To configure IIS, you need to go into the web.config file. We’re using the following configuration in our case:

This solution is working pretty well, and we even noticed that the time to load our scenes has been reduced compared to our previous host. I’m guessing this is thanks to the better infrastructure and network used by Azure datacenters.

However, I have been thinking about moving into Azure for a while now. And my first idea wasn’t to let web site instances serve my large assets. Since the beginning, I have been more interested in storing my assets in the blob storage better designed for that. It would also offer us a possible CDN scenario.

2. Moving Assets Into Azure Blob Storage, Enabling CORS, Gzip Support & CDN

The primary reason for using blob storage in our case is to avoid loading the CPU of our web site instances to serve them. If everything is being served via the blob storage except a few HTML, JavaScript and CSS files, our web site instances will have few chances to autoscale.

But this raises two problems to solve:

  1. As the content will be hosted on another domain name, we will fall into the cross-domain security problem. To avoid that, you need to enable CORS on the remote domain (Azure Blob Storage).
  2. Azure Blob Storage doesn’t support automatic gzip compression. And we don’t want to lower the CPU web site usage if in exchange we’re paying three times the price because of the increased bandwidth!

Enabling CORS on Blob Storage

CORS on blob storage has been supported for a few months now. This article, Windows Azure Storage: Introducing CORS, explains how to use Azure APIs to configure CORS. On my side, I didn’t want to write a small app to do that. I’ve found one on the web already written: Cynapta Azure CORS Helper – Free Tool to Manage CORS Rules for Windows Azure Blob Storage.

I then just enabled the support for GET and proper headers on my container. To check if everything works as expected, simply open your F12 developer bar and check the console logs:

F12 console logsF12 console logsF12 console logs

As you can see, the green log lines imply that everything is working well.

Here is a sample case where it will fail. If you try to load our scenes from our blob storage directly from your localhost machine (or any other domain), you’ll get these errors in the logs:

Console errorsConsole errorsConsole errors

In conclusion, if you see that your calling domain is not found in the “Access-Control-Allow-Origin” header with an “Access is denied” just after that, it’s because you haven’t set your CORS rules properly. It is very important to control your CORS rules; otherwise, anyone could use your assets, and thus your bandwidth, costing money without letting you know! 

Enabling Gzip Support on Our Blob Storage

As I was telling you before, Azure Blob Storage doesn’t support automatic gzip compression. It also seems to be the case with competitors’ solutions like S3. You’ve got two options to work around that:

  1. Gzip the files yourself on the client before uploading, upload it in the blob storage using your classic tools and set the content-encoding header to gzip. This solution works, but only for browsers supporting gzip (is there still a browser not supporting gzip anyway?). 

  2. Gzip the files yourself on the client and upload two versions in the blob storage: one with the default .extension and one with the .extension.gzip, for instance. Set up a handler on the IIS side that will catch the HTTP request from the client, check for the header accept-encoding set to gzip and serve the appropriate files based on this support. You’ll find more details on the code to implement in this article: Serving GZip Compressed Content from the Azure CDN.

In our case, I don’t know any browser supporting WebGL and not gzip compression. So if the browser doesn’t support gzip, there’s no real interest in going further, as this probably means that WebGL is not supported either.

I’ve therefore chosen the first solution. As we don’t have a lot of scenes and we’re not producing a new one every day, I’m currently using this manual process:

  1. Using 7-zip, I’m compressing the .babylon files on my machine using gzip encoding and “compression level” to “fastest”. The other compression levels seem to generate issues in my tests.
  2. I upload the file using CloudBerry Explorer for Microsoft Azure Cloud Storage.
  3. I manually set the HTTP header content-encoding to gzip with CloudBerry.
manually set the HTTP header content-encoding to gzip with CloudBerrymanually set the HTTP header content-encoding to gzip with CloudBerrymanually set the HTTP header content-encoding to gzip with CloudBerry

I know what you’re thinking. Am I going to do that for all my files?!? No, you could work on building a tool or post-build script that would automate that. For instance, here is a little command-line tool I’ve built:

To use it, I could do the following:

UploadAndGzipFilesToAzureBlobStorage Scenes/Espilit C:\Boulot\Babylon\Scenes\Espilit\*.babylon* to push a scene containing multiple files (our incremental scenes with muliples .babylonmeshdata files).

Or simply:

UploadAndGzipFilesToAzureBlobStorage Scenes/Espilit C:\Boulot\Babylon\Scenes\Espilit\Espilit.babylon to push a unique file.

To check that gzip was working as expected using this solution, I’m using Fiddler. Load your content from your client machine and check in the network traces if the content returned is really compressed and can be uncompressed:

Fiddler Web DebuggerFiddler Web DebuggerFiddler Web Debugger

Enabling CDN

Once you’ve done the two previous steps, you just need to click on a single button in the Azure administration page to enable CDN and map it to your blob storage:

enable CDN and map it to your blob storageenable CDN and map it to your blob storageenable CDN and map it to your blob storage

It’s that simple! In my case, I need to simply change the following URL: to Note that you can customize this CDN domain to your own if you want to.

Thanks to that, we are able to serve you our 3D assets in a very fast way as you’ll be served from one of the node locations listed here: Azure Content Delivery Network (CDN) Node Locations.

Our web site is currently hosted on the Northern Europe Azure datacenter. But if you’re coming from Seattle, you’ll ping this server just to download our basic index.html, index.js, index.css files and a couple of screenshots. All the 3D assets will be served from the Seattle node just near you!

Note: All our demos are using the fully optimized experience (blob storage using gzip, CDN and DB caching).

3. Using HTML5 IndexedDB to Avoid Re-Downloading the Assets

Optimizing loading times and controlling output bandwidth costs is not just about server-side. You can also build some logic client-side to optimize things. Fortunately, we’ve done that since v1.4 of our Babylon.js engine. I’ve explained in great detail how I’ve implemented the support for IndexedDB in this article: Using IndexedDB to handle your 3D WebGL assets: sharing feedbacks & tips of Babylon.JS. And you’ll find how to activate it in Babylon.js on our wiki: Caching the resources in IndexedDB.

Basically, you just have to create a .babylon.manifest file matching the name of the .babylon scene, and then set what you’d like to cache (textures and/or JSON scene). That’s it.

For instance, check what’s going on with the Hill Valley demo scene. The first time you load it, here are the requests sent:

Requests sentRequests sentRequests sent

153 items and 43.33 MB received. But if you’ve accepted letting “use additional storage on your computer”, here is what you’ll see the second time you’ll load the same scene:

Only one request shownOnly one request shownOnly one request shown

1 item and 348 bytes! We’re just checking if the manifest file has changed. If not, we’re loading everything from the DB and we’re saving 43+ MB of bandwidth.

For instance, this approach is being used in the Assassin’s Creed Pirates games:

Assassins Creed Pirates gameAssassins Creed Pirates gameAssassins Creed Pirates game

Let’s think about that:

  • The game launches almost immediately after it has been loaded once, as the assets are served directly from the local DB.
  • Your web storage is less stressed and less bandwidth is used—costing you less money!

Now that will satisfy both your users and your boss!

This article is part of the web dev tech series from Microsoft. We’re excited to share Microsoft Edge and the new EdgeHTML rendering engine with you. Get free virtual machines or test remotely on your Mac, iOS, Android, or Windows device @

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