Intended audience. This document is intended as a guide for those who want to do extensive customization on top of Liferay Portal. The extension environment provides a set of tools based on ant to develop your own portlets and extension, to modify the configuration and language messages, etc. It also eases the migration to new versions of Liferay Portal. It is meant for those who wish to customize the portal with their own portlets, configuration, etc that will not be given back to the general public Follow the instructions found in Understanding and Improving Liferay in the Liferay wiki if you want to modify the actual source and contribute your changes back to the project.

Liferay version. This guide has been written for Liferay Portal 4. Some details might be different for previous versions. Do not expect it to be accurate for even older versions.

Related documents. If this is not what you are looking for consider the following related documents

More information and support. If you are looking for help for a specific issue we invite you to use our community forums: http://www.liferay.com/web/guest/devzone/forums to ask your questions. We also offer professional support services (support@liferay.com) where your company will be assigned a Liferay developer ensuring your questions are answered promptly so that your project is never compromised. Purchased support always gets first priority. This business model allows us to build a company that can contribute a great portal to the open source community. If your company uses Liferay, please consider purchasing support. Liferay has an extremely liberal license model (MIT, very similar to Apache and BSD), which means you can rebundle Liferay, rename it, and sell it under your name. We believe free means you can do whatever you want with it. Our only source of revenue is from professional support and consulting.