Desktop app license validation / monetization

[Vouk]

I am currently developing a Qt6 software that I want to distribute commercially. I would like to implement a licensing system that can validate and then activate offline license keys. There should be a website/simple store. There users should be able to purchase/return/etc. the software and updates.

Are there special plugins for Qt6? Which other frameworks are recommended? Which payment service providers process worldwide payments? I am in the EU and the relevant regulations must be met.

[SGaist]

Hi,

In many applications, the transaction happens on the seller's website and the license is activated within the application. That might be a simpler workflow to implement.

[Vouk]

@SGaist Yes, and that's what I actually meant. :)

[SGaist]

AFAIK, there's nothing premade for Qt on that topic.

Beside the payment methods, you also need to determine whether your software can be used offline or if it needs to contact some server somewhere. Note that the last option would render your software useless in case of network disruption.

[Vouk]

It will be used in broadcast / editing studios where no internet connection is available, so an offline installation / license validation is a requirement.

I am sure that some other independent developers have already gained experience with these requirements.

[SGaist]

I did a long time ago but it was when online payment were not that common.

You could check what software such as Sublime Text or GPGTools are using for that purpose.

[Vouk]

I have looked at both projects and decided to go the way GPGTooles goes. On a webserver a license can be bought, and I create a license file which is basically a JSON object encrypted with libsodium using a private/public key. This gets decrypted in the actual Qt app. Once it can be decrypted and the data in the JSON is valid the app can be used.

Thanks for the hints.