Update 8/3/17: I just figured out another workaround to get a delayed send/scheduled email working in Inbox by Gmail
My new method is not 100% manual intervention free, but it is a decent workaround for those that prefer not to use extensions, add-ons or scripts.
Simply write your email, address it and then click the X to close/save the email. This will save the email in drafts. Then go to the Drafts folder, find the message and Snooze it to the date/time you want to send it. At the scheduled time, the draft will come back to the inbox where you can open it and send it at the time you want.
Now this definitely wont work for those that want to send it at a time they are not at there computer or device, such as those that want to make their boss think they are working at 1:30 AM on a weekend, but it still another option of scheduling emails in Inbox.
Are you like me, an really preferring the Inbox by Gmail interface, simplicity, snooze, and reminders? Do you wish you were able to write an email and schedule it to send later? Well, guess what, you can.
How, you ask? Simple. Thanks to a Google Sheets Script written for Classic Gmail by Amit Agarwal, also known as labnol, you can schedule emails.
If you have ever used his script for Classic Gmail, then you understand how it works, and all you have to do is draft your email in Inbox by GMail, save it, and then open up the Google Sheets Script.
If you have not used his script before, you can follow his instructions here. However, instead of drafting the email in Classic Gmail, do so in Inbox by Gmail, follow his intstructions, and BAAAAM! your email is now scheduled to send in the future.
Get a copy of the script here and follow the instructions on the screen.
How excited are you about this?
Thank you and credit to Amit Agarwal (@labnol) for developing this script for all to use.