Apache Synapse is a lightweight and open-source enterprise service bus (ESB) and mediation engine.

It began incubation at the Apache Software Foundation on August 22, 2005,[1] and became a subproject of the Apache Web Services project on January 2, 2007.

After implementing support for legacy systems integration, it moved to a Top-Level Project of the Apache Software Foundation on the February 5, 2008.

Synapse can handle thousands of concurrent requests using little resources and threads.

Synapse supports clustered deployments, with support for load balancing, throttling and caching over clustered deployments.