I started writing this book in August 2022 as a quick reference for myself and other third party developers writing Joomla 4 extensions, or migrating our extensions to Joomla 4's native MVC.

While Joomla 4 has an amazing, rich and powerful architecture and API it does not have any real developer-facing documentation. The documentation you will find is outdated, chaotic and leaves you running for your life.

I am making every effort to make this book approachable to all levels of developers, from the novice who's barely hacked together their first plugin to the seasoned expert with dozens of extensions under their belt. However, to keep things relatively simple and because I am doing this unpaid, on my limited free time, I decided to take a few shortcuts here and there. I do not explain every concept in great detail, I try to explain it in practical detail.

If you want to see what a real world Joomla extension looks like I urge you to take a look at and dissect the Joomla 4 extensions my company, Akeeba Ltd, has published free of charge. The simplest component to start with is Akeeba ContactUs. The most complete combination of a component, plugins and several modules we have published is Akeeba Ticket System — even the free of charge version uses most of the features I am describing in this book.

Hopefully, you will find my approach pragmatic and result-driven instead of a dry, technical document. If you have suggestions for improvement or would like to sponsor this work feel free to contact me through the Contact Me page on dionysopoulos.me.