CiviCRM Developer Guide

!!! warning "Notice" This guide is not yet complete. As of early 2017 we are actively working to migrate content in from the wiki. Read more about this migration process, including how to help out!

CiviCRM is an open-source application. The code can be poked, prodded, twisted, and hacked. It can be customized, extended, and collaboratively developed. This documentation tells you how to do that.

It starts with a high level introduction to get you familiar with CiviCRM development. It covers setting up your development environment, checking whether or not you actually need to implement your own custom code (i.e. you can't achieve what you want through configuration or installing an already existing extension), best practice ways to extend CiviCRM (a.k.a. how to write an extension), things you should know before you start hacking on core, and best practice for testing.

The guide also includes detailed references for tools and subsystems of CiviCRM. These cover topics like the API and hook system and are intended for use by people that are familiar with CiviCRM development.

Editing & reading offline

• This documentation is made with mkdocs and stored in GitHub
• See the "Writing Documentation" section in this guide for specific details on editing this documentation (and others using mkdocs). You can also learn how to read these docs off-line!