There are two competing implementations of Google's protocol buffers in Perl. Neither one is currently being actively developed. Of the two the best is the perlxs implementation. The pure perl implementation is terribly slow with all but the smallest of protocol buffer messages. Neither is hard to use. I should point out that there is actually a third protocol buffer implementation. The difference with this last one is that it is not related, in any way, to the Google C++ implementation, and it is still somewhat lacking in features. It also is not in active development.