The aim of the GreenSoul middleware is to provide a common layer for exchanging event-based real-time information (on the common format) following the publish/subscribe paradigm. The middleware is the most important component in terms of the interoperability requirements of the GreenSoul platform because it interacts with every single layer. LinkSmart middleware uses a SoA-approach ´(Service-oriented Architecture) in order to provide support among various platforms and network protocols. It offers P2P (Peer-to-Peer) communication and device and service discovery capabilities.

The LinkSmart middleware framework will be used to seamlessly integrate GS-ed devices and sensors infrastructure with GreenSoul software applications. LinkSmart was originally developed within the Hydra EU project for Networked Embedded Systems. The final Hydra middleware was renamed LinkSmart and its source code was released to the public. Application developers are provided with a tool that handles physical devices heterogeneity. Using LinkSmart technology, developers can easily control devices using protocols such as Bluetooth, RF, Zigbee, RFID, and Wi-Fi etc. The control is made possible through simple to use web interfaces.