Open source and the App Store

I've seen a lot of confusing information on the internet.

This is also "the internet" so you may get even more confusing information here....

As you suspect the answer does depend on the licence. If you tell us what licence you are considering, you may get a useful answer.

You should also be aware of Apple's minimum requirements for apps' end user licences.

In practice, perhaps the most important question is - is it your code, and if not, what do the authors of the code think about your idea? Trying to make an app from an open source code base against the wishes of the authors of that code could lead to problems; even if you believed that what you were doing was allowed, could you afford the lawyers to argue your case in a copyright lawsuit?

It's my code. I wanted to publish it using GNU GPL / AGPL but I read that you can't.

If it's your own code, i.e. you are the copyright holder, you can do (almost?) anything you want.

You can absolutely publish it on the app store and also release the source with GPL or AGPL licence.

IANAL.