HIBPwned is a feature complete R package that allows you to use every (currently) available endpoint of the API. It’s vectorised so no need to loop through email addresses, and it requires no fiddling with authentication or keys.
You can use HIBPwned to do things like:
Set up your own notification system for account breaches of myriad email addresses & user names that you have
Check for compromised company email accounts from within your company Active Directory
Analyse past data breaches and produce charts like Dave McCandless’ Breach chart
The regular service is extremely useful and Steph’s wrapper looks like it’s worth checking out.