*** Update: It seems that the OpenID library that this add-on depends on has been killed. I do have a copy of the newest version, but I'm hesitant to distributing it as I don't know the reason for killing the original project. I am not planning on going through the efforts of evaluating alternatives and updating the add-on to use some other library. The current plan is just to leave the add-on here as an example of how OpenID can be integrated to Vaadin - it should be quite easy to update the code to use some other OpenID lib if you want to. *** OpenID Integration lets your users use OpenID to log in to your Vaadin application using e.g. their Google or Yahoo logins. By letting your users authenticate using OpenId, they don't have to keep track of yet another combination of username and password (alternatively, the risk they take by using the credentials on every site is slightly reduced). This Add-on is in an early development stage, but it can already be used for basic authentication. An incomplete TODO-list includes: 1) A user interface with fancy buttons for popular OpenID providers and a text field where the user can enter its own custom OpenID 2) Simplified packaging. Either a .zip containing the required third party jar or simply including the dependency in the addon jar using jarjar. (Please tell which option you prefer in the forum) To use the Add-on, you also need to include dyuproject-openid-1.1.7-jarjar.jar from http://code.google.com/p/dyuproject/ on your classpath The add-on jar file contains the source code for the actual integration as well as a simple application (OpenidTestApplication) that demonstrates the basic usage. At this point, feedback, bug reports and feature requests should be directed to the Vaadin Add-ons forum.