[Answered ]-Software as a service in Django – many companies should be able to have the same users

The solution is to have a ManyToMany relation between User and Company.

All Users are admin of their own Company (happens when they create their account), but in addition they are also candidates of other companies.

They can add Items for all companies they are in, but only invite new people for the company they’re owner of, all using the same user account.

You’ll need some way to switch the company they’re currently working as, or showing all of them on the same screen, etc.