Build a Feathers UI project as a Neko VM desktop app

Feathers UI may be used to build desktop applications targeting the Neko virtual machine.

Note: Targeting Neko is best suited for debugging purposes only. For production applications, consider targeting HashLink or native C++ (with the Windows, macOS, and Linux targets) instead.


Follow the standard Feathers UI installation instructions.

No additional dependencies are required to target the Neko virtual machine.


To build for the neko target, run the following command.

openfl build neko

Use the -debug flag to create a build to include extra debugging information, including full stack traces when there's an exception or crash.

openfl build neko -debug

The build's output will be written to the bin/neko/bin folder.

Your project.xml file may optionally specify an output folder different from bin.

<app path="Export"/>

In the example above, the output would be generated in Export/neko/bin instead.

Run / Debug

OpenFL provides the test command to launch your project using the Neko virtual machine.

openfl test neko


In the future, common error messages and their solutions will appear in this section.

Did you get some other error message that you don't understand?

Configuring OpenFL builds for various targets can be a little tricky! Head over to either the Feathers UI community forum or the Feathers UI Discord. Explain which command you tried to run, be sure to mention that you are targeting neko, and post the error message (and any additional relevant output). Ideally, we can help you figure out a solution, and then we'll also add it to this troubleshooting section, so that everyone can benefit.