If you are an app developer using AI2 or any other distros of App Inventor then you'll need extensions to push the limitations of your app.

However, there are many developers all around the world who provides their Extensions for free or for a little donation.

But, If you have a little knowledge in Java and wanted to make your own extensions then you are at the right place.

Here we're going to discuss all the sources that made making extentions easy.

Let's go from the easy one & recommended for the beginners and simple extentions.

Extension Builders Online - Kodular IDE & Appybuilder Editor.


These are the online tools for making your own extensions. They are FREE to use.

These are for the beginners of extention development who has no knowledge to set up the java JDK and ANT.

These come with the basic syntax (the code which is required compile an extension) in default.
So it will be very easy for you to build an extension.

Appybuilder's Code Editor also have many other functions. Check them out -Appybuilder Editor.

Kodular IDE is fast and reliable for extension making - Kodular IDE


Make Extensions Offline - App Inventor sources


Firstly you need to download :




GIT (Recommended)

Any Java Editor / Java IDE ( Notepad ++ would be better option else VS code)


 1. Installing Java JDK

Set the Environmental Variables of your pc to :

Set JAVA_HOME to where you installed Java JDK.
For example: C:\Program Files\Java\jdk1.8.0_131

Edit PATH and add those:

%JAVA_HOME%/bin, %JAVA_HOME%/jre/bin, C:\ProgramData\Oracle\Java\javapath

Make a quick check of Java JDK installation by

bash $ java -version java version "1.8.0_131" Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
 Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)


2. Installing Apache ANT

Unzip the folder and move it to a place where it is safe. I want to place it in Drive C so the path would be " C:\apache-ant-1.10.1 "

Now set the Environmental Variables:

Set ANT_HOME to where you have the Ant folder placed. 

For example: C:\Ant\apache-ant-1.10.1

Edit Path and add %ANT_HOME%\bin

Edit ClassPath and add %ANT_HOME%\bin


Make a quick check of Ant installation:

bash $ ant -version Apache Ant(TM) version 1.10.1 compiled on February 2 2017

3. Installing GIT

This tutorial may help you in installing the GIT 

How to Install GIT - Atlassian

4. Now Unzip the App Inventor Sources

After you unzip AI sources write your java code for the extension using Notepad++ or VS Code.

You can have a look at the basic syntax which is required.

Check it on GITHUB here

After you write the code place it in --( appinventor-sources/appinventor/components/src/com/PACKAGE_NAME/EXTENSION_NAME.java)

Now get to the appinventor folder of the sources

Right click and select GIT BASH HERE

After the command prompt opens up 

Type "ant extensions" Enter

After the build completes if you get BUILD Successful then congratulations you have built your own extension

Else if you see BUILD FAILED then you might have set something wrong.
Or
It shows up error message which has errors in code with the line number beside it. Check your code and fix the errors.

Adding New Libraries

To add new libraries you must add the .jar files to the lib folder in the AI sources and update the build.xml file to import new libs.