This deliverable is the output of tasks 3.1, 3.2 and 3.3. It presents the final version of the DOML (v3.0). DOML is a domain-specific language designed for modelling the cloud applications and the infrastructural resources, hiding the specificities and technicalities of the current IaC solutions and increases the productivity of these teams. DOML is complemented by DOML-E (KR4), which is the set of extension mechanisms defined for the language. They allow new infrastructural components, e.g., for software execution, network communication, cloud services, or data storage, to be incorporated in the DOML language. This deliverable presents the DOML metamodel and syntax and its extension mechanisms, DOML-E. Moreover, it includes an overview of the changes in the language since the previous deliverable D3.2 and discusses about the level of accomplishment of the requirements formulated within the PIACERE project. A preliminary evaluation of DOML is presented together with some examples of DOML usage. Finally, the deliverable includes an overview about the lessons learnt and future directions for the extension of the language beyond the scope of the PIACERE project.