Sensor networks have expanded their scope and capabilities, becoming a fundamental part within the Internet of Things (IoT). To be able to meet the interoperability needs, it is necessary to have a repository of the sensors' data and observations, with this end in mind, the Sensor Observation Service (SOS) has been created; however, after several years since its last update, many technological changes have accumulated. This paper proposes and evaluates a SOS with a REST architecture and a JSON over HTTP message exchange, which is used to interconnect sensors networks and, at the same time, improve the performance of these networks and facilitate their deployment within the IoT.