#chatmail is not a replacement for Whatsapp in the traditional sense. It's a small machine that can be tweaked in many ways. The tweakability of the e-mail system is in it's DNA and practises ... that is the antithesis to WA if you like :) What drives nine.testrun.org, the first public chatmail service, is fully visible at github.com/deltachat/chatmail -- a minimalist config and setup, some python modules and tests, standard postfix/dovecot. co-incidentally pretty fast but there is a twist ;)