Is it possible for the same user to access multiple Artifactory instances?

Yes, there are two methods to achieve that:
 

  • Using Access Tokens: One of the big advantages of access tokens is the fact that you don't have to create a user in Artifactory to use them. When creating a token, you can specify a username that does not exist, and Artifactory will create a transient user that will only exist as long as the token is valid.

 

  • ​Using user plugin like this, this user plugin replicates security data includes all users, groups, and permissions, and all associated data, including user passwords, API keys, OAuth keys, etc