Nylas is really cool. If I remember correctly they are building a base email application that can be extended with plugins (like the atom editor). This does re

Nylas is really cool. If I remember correctly they are building a base email application that can be extended with plugins (like the atom editor). This does require people to adopt their email client. The InboxSDK takes a different approach in that it lets you extend Gmails functionality and write apps for Gmail. End users don't have to switch their email client (assuming their using the gmail web client)