Nice to see you slumming with us here Simon,
For the avoidance of doubt, I assume you refer to the plethora, the wealth, the cornucopia of Application Program Interfaces we now enjoy on the IBM I platform? and not the API's that exist for other tooling, or the 'jump on the bandwagon' so called API's which vendors self proclaim?
Me? Well, I've spent some time trying to find a comfortable, simple, repeatable way to integrate the use of an IBM i API into 2e, and whilst its doable, it has to be said that it's lumpy.
The expectation set by the simplicity and clarity of 2e out of the box is high, and having to resort to user source, and plug bits of user source into a function in the right places seems slow and unwieldy, whilst intellectually interesting, compared to the productive and relatively error free use of the base 2e product. Adding some facilities to integrate calls to API's (or user produced procedures) with the simplicity and accuracy we expect of 2e would be a major step forward, so yes, I'd be interested in more information.