A critical challenge faced in Internet of Things (IoT) is the heterogeneous nature of its nodes from the network protocol and platform point of view. To tackle the heterogeneous nature, we introduce a distributed and lightweight service bus, LISA, which fits into network stack of a real-time operating system for constrained nodes in IoT. LISA provides an application programming interface for developers of IoT on tiny devices. It hides platform and protocol variations underneath it, thus facilitating interoperability challenges in IoT implementations. LISA is inspired by the Network on Terminal Architecture (NoTA), a service centric open architecture by Nokia Research Center. Unlike many other interoperability frameworks, LISA is designed specifically for resource constrained nodes and it provides essential features of a service bus for easy service oriented architecture implementation. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).