lixa
LIXA, LIbre XA, is a free and open source XA transaction manager
...LIXA is a Transaction Manager but it's not a Transaction Monitor: this is the distinguishing feature of the project. LIXA technology enables every application container, like a web server or a shell, to become a two phase commit application server. The client/server architecture of LIXA allows many application containers to share a single LIXA (state) server: this is ideal when horizontal scalability is a must and many identical application containers must refer to a single transactional environment.
LIXA can be used with the C, C++, Java, Python and COBOL programming languages.