Can Piwik manage multiple user accounts?
In Piwik, you can create an infinite number of users and websites to track. For each user, you can set permissions to “view”, “admin” or “no permission” for a specific website, or for all websites at once. The permission system in Piwik is simple and makes it very easy to manage from a small number of websites and users to hundreds of websites and thousands of users. See the Manage Users documentation.