To give you a brief intro, Gist gives you the tools to build and integrate in-app messages into Web, iOS & Android.
Think of Gist as a tool within your toolbox, like how you would use Mailgun for transactional email or Twilio for SMS. Gist does the same for in-app messages, it offers an API to queue personalized messages and a message builder to create cross-platform messages.
In October I'll be removing the invite system so anyone can just go in and create an account. If you want to be reminded when that happens please add yourself to this list.
Please have a look at Gist and let me know your thoughts.