Cross platform tracking with User-IDs across web, iOS and Android apps?[ Edited ]
June - last edited July
I've got a website where users are required to log in, in order to get the basic services and functionality. Been thinking of implementing user-IDs for a while but have not managed to do so until now. Meanwhile I've been working on iOS and Android mobile apps and will be launching soon.
How do I track my users across those 3 platforms in a single view - e.g. track customers who say for last 30 days have logged in to my website AND ALSO logged to my Android app?