The underlying design of Obtree WCM means it is very simple to expose all content, templates, images and other component objects either directly, or formatted as wrapped structured data.
Obtree WCM has, out-of-the-box, a number of SOAP interfaces (so-called 'managers') that allow both retrieval of, and interaction with, various aspects of the system. This model of object access, while core product, is aimed at complex integrations.
Further, all objects - if given a URL - are instantly accessible over HTTP(S), though the object contents will be returned as-is, with no structural or formatting wrapper.
We can can very easily develop a simple interface to retrieve and present content wrapped in XML or JSON, in response to a structured URL, using the Obtree WCM scripting layer. This can be extended to return lists, or include a simple API to get texts, or images, or templates.
In other words, a simple REST API.
Please see the technical discussion page for further details of how this can be achieved with Obtree CMS.