Before Rock can send a single email or text, it needs to know how to hand your messages off to a delivery service. That handoff is a Communication Transport: you plug in the details your provider gives you, and Rock takes care of the rest. Find your transports at Admin Tools > Settings > Communication Transports. Rock ships with several, including SMTP, Mailgun HTTP and SendGrid HTTP. This page is the overview; for the step-by-step of a specific provider, including keys and webhooks, see Email Integrations. NoteSMTP Relaying May Bite YouIf you use SMTP for development or testing, make sure the server or service is set to let your Rock server relay. Using Google Apps for this? See the tips in Email Integrations.