Which part? We are a Django stack, though with our own framework over it: https://github.com/nyaruka/smartmin https://github.com/nyaruka/smartmin The main Flo

Which part? We are a Django stack, though with our own framework over it: https://github.com/nyaruka/smartmin https://github.com/nyaruka/smartmin The main Flow UI leans heavily on JSPlumb. We use Angular JS for our analytics side and use the mad combination of HAML, Coffescript and LESS to avoid writing closing tags in anything at all.