Concept2 Forum

I'm studying computer science and I'd like to make an app for Concept2 ergs as a project. What language is Ergdata, Ergzone etc. written in? Is there a recommended approach? As they are Android and iPhone apps, I'd suggest looking at their native platforms, or something that is crossplatform, like ...

I'm studying computer science and I'd like to make an app for Concept2 ergs as a project.
What language is Ergdata, Ergzone etc. written in? Is there a recommended approach?

I am looking to use Flutter to create an app, does anyone have any advice on this?