ZAP documentation for developers. This is currently being worked upon and more articles will be published soon.
A Quick Start Guide to Building ZAP - learn to run ZAP from source using only the command line
Building ZAP with Eclipse - How to build and run ZAP using the Eclipse IDE
Building ZAP with IntelliJ IDEA - How to build and run ZAP using IntelliJ IDEA
Creating a New Add-on in zap-extensions - A quick way to create a new add-on