UPDATE: There is a work around available to allow friends to access Google Inbox from their phone. Here is the information: How to Access Google Inbox without an Invitation. Please let me know if this method still works. It should help you get Inbox without an invitation.
I have received an invite and have learned that each person that receives an invite will have three (3) invites to share shortly after they first sign in to Google Inbox. When I get my three (3) invites I will share with those in the comments below only if they promise to share with others from the comments. That way, everyone that has commented will get an invite.
Here is a Vine of what Inbox looks like on Android. It is almost identical to iOS:
On Wednesday, October 22nd, 2014 Google announced “Inbox” by Gmail which is an enhanced Gmail service. Think of email on steroids. Instead of just getting text based emails you can now confirm directions, appointments, connect with friends and pretty much everything else related to socializing through the web. Very much like Gmail back in April of 2004 Inbox is only available to those with an Invitation. This is sure to change in the near future but as of October 2014 you must have an invite to access Inbox. With that in mind, I am opening up my comments to allow anyone seeking or willing to send out an invite to communicate.
If you are looking for a Google Inbox invite please comment that you are looking for an invite and your email address. If you have invites to give make sure to let it be known. I would imagine Inbox will be very similar to Gmail in that the first batch of Beta users will get 100 or so invites. At this point I do not have any invites and I have yet to use the Google Inbox. It is important to note that Inbox looks as if it will work much better on Android when compared to iPhone or iOS products. That said, with Google being so good at Gmail it is hard to imagine this service won’t be amazing on all devices.
Without further ado, start the communication and get some invites spread to your friends and family. Also, if you have extra invitations please send me one at email@example.com.