--- 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. == Installing Installing add-ons from Vaadin Directory is simple, just adding a Maven or an Ivy dependency, or downloading the JAR package and and dropping it in the web library folder of the project. [[figure.addons.maven.widgetset]] .Role of the widget set image::img/addon-architecture.png[width=75%, scaledwidth=80%] Most add-ons include _widgets_, client-side counterparts of the server-side components used in the Vaadin Java API, as illustrated in <>. The _widget set_ needs to be compiled into the application widget set. Adding the dependency in Maven projects and compiling the widget set is described in <>. The section also describes how to use the online compilation and CDN services during development. For Eclipse projects that use Ivy for dependency management, see <>. You can also download and install add-ons from a ZIP-package, as described in <>. == Add-on Licenses 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 <>. == Feedback and Support 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.