Timo Sirainen, born 1979, is a Finnish programmer also known under the handles "cras" and "tss". Sirainen is the original author of the IRC-client Irssi and the POP/IMAP server Dovecot. Sirainen lives in Helsinki, Finland.
In 2006, Sirainen began studying biotechnology at the University of Tampere.
He was formerly working for Rackspace Email & Apps (formerly Mailtrust), where he continued the development of the Dovecot POP/IMAP server.
Since May 2011 he runs his own company offering commercial support for Dovecot. In March 2015, Dovecot Oy became part of the Open-Xchange Family.