In digital libraries Learning Objects (LOs) are widely used for teaching because they can be reused in alternative contexts. Thus, a key requirement of LO tools is preserving the reusability advantages of fragments while simultaneously enabling end-users to deal with LO-level granularity and higher-level requirements. These perspectives are usually reflected in the information and content models, but software developers then suffer the complexity of manipulating both abstraction levels at once. This article describes ContentCompass Reference Architecture (CCRA), a layered reference software architecture for digital libraries in the learning domain that addresses this problem by assigning LO- and fragment-level tasks to user-level Web applications and core Web services, respectively. The CCRA is freely available, and has been already used to implement a LO recommender and composer for the Chilean history teaching community. © 2012 Springer-Verlag.