As the complexity of intelligent environments grows, there is a need for more sophisticated and flexible interfaces. Conversational systems constitute a very interesting alternative to ease the users’ workload when interacting with such environments, as they can operate them in natural language. A number of commercial toolkits for their implementation have appeared recently. However, these are usually tailored to specific implementations of the processes involved for processing the user’s utterance and generate the system response. In this paper, we present a modular architecture to develop conversational systems by means of a plug-and-play paradigm that allows the integration of developers’ specific implementations and commercial utilities under different configurations that can be adapted to the specific requirements for each system.