In this paper we propose a complete platform-independent fault-tolerant layer for multi-agent systems, which is able to support heterogeneous agent platforms from different vendors. Our solution incorporates the usage of the J2EE architecture, Web-services and the persistent publish/subscribe messaging model to allow negotiable support and guarantee the exactly-once consumption of messages. It greatly improves the reliability of multi-agent systems and produces insignificant runtime overheads. We present the layer's conceptual architecture and conclude this paper with a performance analysis of the solution.