Different database and URL configurations

Hi,

I'm running a single application for different customers, in version 3 of CI i've made things work on different settings from the same application. Now i'm rebuilding everything in CI4 with the same idea but i think it might work in a better way than my current configuration in CI3.
Does anyone have any tips on how to make this work properly?


Idea:

• I've got a master domain wich will run the application with default database that holds customer information and configuration
  
• All my subdomains use the application from the master but running on his own database.