How long does it take before the master data is visible in the app?

This differs per cash register system and whether the master data should be sent automatically or manually. If the master data can be sent manually, then it will be processed automatically within 5 minutes, once the data is received. If the master data is sent automatically, then this will take a night to process. Rule of thumb here is, that if it is added today in the POS system, it will be visible in the app the next day.