Using an IP as a OAuth Redirect URI

Don’t believe so

A use of a domain can help prevent things being redirect to the wrong place. Also you just shouldn’t be using an IP address to server a website.

An IP address identifies a computer/server. From there Web Server software like Apache/Nginx determines what content to returned based on the incoming domain request.

Further more in order to use SSL you will need a domain. And whilst SSL is not required, it is advised to help users be happy about security and your handling of any credentials