A way to detect course completion

Hi, I'm new to working with ALM, so the question might be obvious.

We're looking for a way to detect when a user completes the enrollment, preferably in real time. I've been looking at the available API and I haven't found any way to achieve that.

The only thing I found was that I could get the list of all the users and then get all the enrollments for each of the users. Then I'd have to check the completion dates of those and run this periodically comparing the completion dates again the last check date. This seems like a lot of traffic that will mostly return nothing.

So is there something I've missed that would allow me to subscribe to some events? Or maybe at least there's some kind of journal/even log that I could periodically pull and find the enrollment completions there?

Thanks for all the answers