This deliverable defines and describes the Experience Engine, one of the core components of the MaTHiSiS back-end. Its main objective is the materialization of a learning scenario for a specific learner in a specific context. In order to establish the theoretical background of the concepts used by the Experience Engine, the Learning Action Ontology is first introduced to describe the categories of Learning Actions (LA) and Learning Materials (LM) involved in the system, as well as how they can be associated together. Implementation details on the integration of these concepts are also provided through the description of the LA library and LM library and their Open APIs and data models. In addition, the early front-end used to manipulate these entities is described to give a complete overview.