  Recommender systems in academia are not widely available. This may be in part
due to the difficulty and cost of developing and maintaining recommender
systems. Many operators of academic products such as digital libraries and
reference managers avoid this effort, although a recommender system could
provide significant benefits to their users. In this paper, we introduce Mr.
DLib's "Recommendations as-a-Service" (RaaS) API that allows operators of
academic products to easily integrate a scientific recommender system into
their products. Mr. DLib generates recommendations for research articles but in
the future, recommendations may include call for papers, grants, etc. Operators
of academic products can request recommendations from Mr. DLib and display
these recommendations to their users. Mr. DLib can be integrated in just a few
hours or days; creating an equivalent recommender system from scratch would
require several months for an academic operator. Mr. DLib has been used by
GESIS Sowiport and by the reference manager JabRef. Mr. DLib is open source and
its goal is to facilitate the application of, and research on, scientific
recommender systems. In this paper, we present the motivation for Mr. DLib, the
architecture and details about the effectiveness. Mr. DLib has delivered 94m
recommendations over a span of two years with an average click-through rate of
0.12%.
