--- title: Overview order: 1 layout: page --- [[addons.overview]] = Overview In addition to the components, layouts, themes, and data sources built in into the core Vaadin library, many others are available as add-ons. link:http://vaadin.com/directory/[Vaadin Directory] provides a rich collection of add-ons for Vaadin, and you may find others from independent sources. Add-ons are also one way to share your own components between projects. Installation of add-ons from Vaadin Directory is simple, just adding an Ivy or Maven dependency, or downloading the JAR package and and dropping it in the web library folder of the project. Most add-ons include a widget set, which you need to compile, but it's usually just a click of a button or a single command. After trying out an add-on, you can give some feedback to the author of the add-on by rating the add-on with one to five stars and optionally leaving a comment. Most add-ons also have a discussion forum thread for user feedback and questions. Add-ons available from Vaadin Directory are distributed under different licenses, of which some are commercial. While the add-ons can be downloaded directly, you should note their license and other terms and conditions. Many are offered under a dual licensing agreement so that they can be used in open source projects for free, and many have a trial period for closed-source development. Commercial Vaadin add-ons distributed under the CVAL license require installing a license key as instructed in <>.