Michael from Inbox here. We've spent a lot of time working to get the API semantics right, to be both backwards compatible and support modern development. One big benefit of using Inbox vs. Gmail's API is that Inbox also works with Yahoo! Mail, Outlook/Hotmail, Microsoft Exchange, and may more coming soon. Plus it's open source, so you can run it yourself. :)
Anyone here should feel free to ping me with questions. I'd love to hear feedback about the docs, and can set you up with an invite to the hosted version (think Heroku) which is coming soon. mg@inboxapp.com
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