How to start - programmatically create and manipulate ai files?

Hello!

I'm a developer and have the task of creating a generator of ai files, based on a template, while manipulating certain fields and contents of that template (text, formatting and images). I read through several documents for getting started, plugin development and even through third party sdk's and tools to achieve that. But now I'm kind of lost in the decision, which is the best way to start. Should it be a plugin/extension, and are they even suited to create several documents out of a template? Or is there a solution with the help of some SDK that allows this task with an external application?

I know the sdk documentation offers a lot of content and examples. I'm merely asking for opinions about which is the right way to go.

Thanks in advance!

Stefan