Hello World

Try the simplest piece of code possible

To verify that the Royale SDK is set up correctly, we recommend you create and build a “Hello World” example. If that works, you can move on to Create an Application and work through the tutorial on building a more substantial application.

These instructions presume you are not using an IDE, but are creating files in a text editor and compiling using command-line scripts or similar controls. Development tools that fully support Royale provide their own instructions for building your first Royale applications.

In our Apache Royale Blog Examples, you can read about the ‘Hello World’ example to complement the information exposed here. Notice that the main difference is that while in this Hello World we use the Express library, in the blog example we use the Basic version that requires a few more lines of code.

Create the project folders

Create or select a folder to hold this application’s source and output.

In that top-level folder, create a folder called HelloWorld (it can be named something else if you want, and the name can contain spaces). This folder will be referred to as the project folder throughout the documentation.

In the project folder, create a folder called src. You can use other names, but the compiler will manage your output folders for you if you use src or src/main/royale (src\main\royale on Windows).

So, if you used a folder called Projects for all of your project folders, then you would have the following folders:


Create the source file

In the src folder, create a file called HelloWorld.mxml and use your favorite text editor to give that file the following contents:

<?xml version="1.0" encoding="utf-8"?>
<js:Application xmlns:fx="http://ns.adobe.com/mxml/2009"

            <js:Label text="Hello World" />

Compile the source file

If you used NPM to install Royale, run from your project folder:

mxmlcnpm src/HelloWorld.mxml

If you didn’t use npm, run:

<path to SDK folder>/js/bin/mxmlc src/HelloWorld.mxml

Run the output

If the compiler reported success, there should now be a bin/js-release output folder in your project folder, such as


In that folder should be an index.html file you can open in your browser to see your “Hello World” application. If you see that, congratulations! You have installed Royale successfully and are ready to build Royale applications.

Create an Application contains a tutorial for building a more substantial application. The Royale SDK includes an Examples directory that provides practical demonstrations of how to achieve many features and effects using Royale.