Hey! nice to hear from you again :) Thanks for the great feedback...

Good call on the mission critical aspect, we spent a lot of time of that side of things - so even more reason to highlight.

I think we have a few blogs posts lined up which discuss technology, as you can imagine we use quite a few things. As a quick overview we use some relational and no-SQL dbs, a bunch of Java with some Hadoop and Cassandra thrown into the mix :). Node.JS and AngularJS for the front-end servers.