X-REST 1.60 is a REST API for XOOPS 2.x series. It will work with earlier version of xoops as well upto XOOPS 2.5. It provides a full REST API with JSON, XML and Serialisation Responses. It uses the standard plugin set for the other APIs as well as this one to provide a streamlined solution to APIs on your site.
The plugins are not compatible with all other API by chronolabs. You may be familar with a REST api such as the ones at Google, Twitter, Facebook etc, this is just the same but allowing for API Action on your own website. There is two reserved variables on the REST API which are the following: xrestplugin & outputmode.