You may want to have the wp2print site linked to an external site in such a way that users do not need to log-in 2 times when moving from the external site to the wp2print site. Users are expected to login to the external site first. In the external site, the user will click a button. The user will then be re-directed to the wp2print already logged-in. This entire process is called "Single Sign-on".
wp2print contains an API that permits account functions from external sites. The API includes 3 methods:
The exists method allows the external site to test whether an account already exists for a given username. The data method allows the external site to create new user accounts and to update the data in an existing user's account in wp2print. The login method allows the user to be automatically logged in when they arrive from the external site.