The easiest way to extend Halvr is to create custom Freemarker templates. Freemarker is used by layouts and widgets for rendering.
Widgets
We provide a simple widget interface to create custom widgets. Widgets are for instance queries to our search index like the list or table widget, but can be anything else that can be embedded into pages, blog posts, tasks, ...
The video below shows how you can edit the templates and install the modifications as plugins.
Actions and Services
You can create custom extensions for close to every piece of the application. Even custom Stripes ActionBeans or custom services can be added to Halvr.