The EBooks systems most libraries use is run by Overdrive, which manages the library’s digital collection, the loan periods, the accounts, etc. they do a pretty good job, and their phone apps (Libby) is quite good.

My only real complaint about Overdrive is the premise that a copy of a book can be lent out x times. It’s a concept pushed by the publisher trying to create scarcity where none exists. Overdrive can’t do anything but capitulate. I suppose I’m also bothered by the “x copies available” concept.