Does Manager expose APIs for developers ? If yes, could someone provide reference to it ?
There is API in server edition and cloud edition. You can access it by navigating to
/api. Then log in with username and password.
API is still work in progress. There is no documentation yet but it is relatively self-explanatory.
Is it possible to get handle over code or contribute to development of manager ? Need to setup own cloud edition and have product use it for customers.
You can use server edition in white-label mode which will strip all branding and offer cloud accounting to your customers under your own brand. There are some companies doing just that.
This is wonderful. Can you pls throw more light on this. How do I go about that?
At the bottom of the Support page in the desktop edition, click the button:
How to become a partner?
See my earlier answer.