Systems Biology Workbench (SBW) is a simple framework for application intercommunications. It allows heterogeneous application components written in diverse programming languages and running on different platforms to communicate and use each other capabilities via a fast binary encoded-message system. It uses a broker-based, distributed, and message-passing architecture. It supports many languages including Java, C++, Perl, and Python. SBW enables applications (potentially running on separate or distributed computers) to communicate via a simple network protocol. The interfaces to the system are encapsulated in client-side libraries that we provide for different programming languages.