You should only build software tools that at the right level of abstraction to deliver your product. Building APIs for anything else is a waste of time unless there is a general absence of those tools in the marketplace. If there is or existing tools are overpriced, slow or otherwise untenable, then maybe you should work on tools for that market instead.
Otherwise, after product market fit and as you scale you can go down the abstraction hierarchy to optimize cost of goods sold.
Otherwise, after product market fit and as you scale you can go down the abstraction hierarchy to optimize cost of goods sold.