If you are an agency, you surely have the same problem that we had: Over time, you are responsible for a huge number of Mautic sites, probably with multiple users on each. This is not a good situation, because changing passwords, adding or removing users becomes virtually impossible and thus an actual security threat. Unless... you run a central login service technology!
Auth0 is a well-established, professional Single Sign-On SSO solution for this problem, and we have been using it for a while in other areas (read;: TYPO3 CMS). Today we are more than happy to share with the world: Our Mautic Auth0 authentication plugin.