Polymail is an email productivity platform for Mac and iOS.  It was created by Brandon Foo, Brandon Shin, and Shahan Khan in 2015. Polymail takes inspiration from Dropbox email client, Mailbox's, simplistic and elegant design and 'inbox zero' philosophy (ie: email inboxes should always have zero new mail after checking).  Polymail has won numerous design awards including Product Hunt's 2015 Mac app of the year award and The Next Web's 2015 app of the year award.  
Polymail participated in Y Combinator's Summer 2016 program.
Polymail adds several new features atop those associated with standard email. Its email tracking shows which recipients have received and opened the email Users can also set reminders for when to follow-up on an email and schedule when they want their emails to send, if not immediately. The app also holds emails briefly so that users can "undo send". Polymail will also show profiles for the user's recipients and senders by associating those email addresses with those used in other social network services.
The apps for OS X and iOS platforms released to the public on July 20, 2016.
Matthew Hussey of The Next Web wrote in December 2015 that Polymail was the first email app he genuinely loved, and praised its improvements upon Gmail's interface.