Which URL to use to link smartphone to run.events App?

Under Consideration Luca Vitali ● ago

Hi Support,
we want to add a QR Code on the backside of our event badge to point smartphones to run.events App.
Ideally this link should open run.events App if it's already installed on the Smarphone, or point to the appropriate store (Android or Apple) to download it.
Which is the best URL to do that?
Thank you
Best Regards