How do I get a list of all users from the API?

Using the “new” flag instead of “active” should give you ALL the users. Just sort by created ascending and it will give you all the users ordered from oldest to newest. You will still have to use pagination to fetch all the users otherwise it could be way too large of a request if you have a lot of users.

/admin/users/list/new?asc=true&order=created&page=0