Integration Budget control with 3rd party application

Summary:

We need to integrate Budgetary control with 3rd party application.
It is extremely important when Purcahse transactions are created in external application and the external application requires to perform a funds check and also reserve funds.

We don't have encumbrance acccounting enabled but only budgetary control. So, Is there a way to import consumption from external system? there must be API available to reserve the amount from external system and of course also an API to check funds.

thanks