We're an interoperable messaging platform that brings email, SMS, Facebook Messenger, and even social networks together and allows you to manage all communication with upgraded privacy, lots of plugins and customizability.
Privacy is super important to us; to the extent that you can, make the brand look like something you can trust with your messages.
I'm not a fan of gradients, and generally prefer a flat design - however, if you feel like you have a great take that breaks these rules, don't let it limit you - just be sure that it's something you think is going to be really great.