The largest commercial provider of ebooks, audiobooks, and other digital content such as streaming videos in the world, a 2023 report estimated its market share as perhaps being upwards of 90%.
This company notably powers the Libby app for borrowing books.
The headquarters is located in Cleveland, Ohio, United States.
Are there any European alternatives available?
If you only use the digital services of your library you may also sign up in a different city. I was member of the Berlin library for a couple of years because it had the best overall service for me but never lived in or close to Berlin.
That’s a good tip, although around my way it’s standard to need to visit a local library at least once in order to finalise sign-up (in the UK it’s standard to need to show photo ID when signing up, and libraries won’t generally bother setting up a way to do that remotely).
I know one person who happily collects library memberships every time they’re in a new area with a bit of time on their hands though. They’ve got a very impressive wallet-full of library cards!