Bossa is a workflow engine written in Java. The engine is very fast and lightweight, without sacrificing functionality. Its main strengths are the very expressive Petri net based notation it uses to define workflows and the powerful resource selection mechanisms it provides. Also, it is free software licensed under the GNU GPL.

Bossa does not require a RDBMS and is very simple to use and to integrate with java applications. Actually, it was designed to be embedded. Therefore, Bossa is organized as a library to be used by server side applications (especially web oriented ones) that need workflow services.

The characteristic that makes Bossa at the same time simple and powerful is the clear separation between workflow logic and application logic. We believe that the application's workflow logic should be abstracted in the same way that RDBMSs abstract the application's data storage and retrieval concerns.