Vert.x is a polyglot application framework for building highly concurrent and scalable applications on the JVM. It allows applications to be written in multiple languages including JavaScript, Ruby, Python, Groovy and Java. Vert.x uses an event-driven and asynchronous model with shared event bus to enable communication between verticles (deployable units) running on single or multiple JVMs. It provides tools for building TCP/SSL servers, HTTP/HTTPS servers, websockets and distributed shared maps and sets.