easyrec is a recommender system that aims for easy integration of recommendations into web applications. It has a web based admin tool, and its recommendation engine is accessible through a REST API, providing methods like 'other users also bought'
IRSA is a toolkit for Information Retrieval Service Assessment.
...It builds upon the Grails Web Framework and is developed at GESIS.
It implements two main functionalities: (1) A number of showcases that show the implemented services like a so-called Search Term Recommender and different science-model based ranking mechanisms and (2) an IR assessment module that let's one do an interactive evaluation of the retrieval services.
All implemented services are available via well-documented RESTful API. This toolkit is distributed under an Apache License 2.0.