This paper describes the results of a joint work between partners in ITEA2 12004 Smart Energy Aware Systems (SEAS) project, which aims at developing an ecosystem of distributed services that target energy efficiency. This paper particularly focuses on Electric Vehicle (EV) need for smart charging, which is made possible with Internet-of-Thing (IoT) capabilities and smart grid deployment. A use case is proposed by Compagnie Nationale du Rhône (CNR) to tackle the emerging need for electric mobility. In this CNR scenario, a new player, named Smart Charging Provider (SCP), exposes a charge plan optimization algorithm on the Web. This service can be used by any Charging Station Operator (CSO) over the world in order to optimize their charge plans. These optimizations are computed with respect to economical or environmental criteria, while ensuring the satisfaction of constraints expressed by EV drivers and CSOs. Apart from describing the actual implementation and deployment of this service as a RESTful Web service, this paper also overviews three of the main contributions of SEAS project that were used together to achieve this goal: (1) SEAS Reference Architecture Model, designed to enable real-time interconnection of any energy actors; (2) Multidimensional Quantities ontology, used throughout SEAS ecosystem to quantify systems and their interconnections; (3) SPARQL-Generate language and protocol, implemented to ensure semantic and syntactic interoperability at low cost in SEAS ecosystem.