I built this crazy seamless system (Not sure, how its done usually in the industry), Where we are acquiring users on the web funnel, making them pay on the web, and after purchase they land on the mobile app which is already authenticated even when it is not installed (thats the main sauce btw), ...
Source: [Dev.to](https://dev.to/utkarsh4517/the-web2app-funnel-where-users-pay-on-the-web-and-open-the-ios-app-already-logged-in-even-before-456f)