I’d like to provide accounting tools for small-press and indie book publishers. Manager looks perfect. But I have many questions. I’ll start with just two:
Is there an API that enables automation of new user accounts, e.g. say a new small-press or indie book publisher?
Is it easy to customize Manager for needs of my subscribers?
That depends on what you are trying to do. In general, the customization available is easy to implement. But all customization must be done for each individual business. You cannot customize multiple businesses at once. What you can do is create a standardized model business with no transactions, but full selection of active modules, theme customization, default form content, and so forth. That model business can be saved as a backup. Then, for each new business, you could import that model business.