Boxy is to Google Inbox what Mailplane is to Gmail: a hybrid tool that combines advantages of your web browser with the advantages of a native app.
Like Mailplane, Boxy looks and behaves about 97% like Inbox running in Chrome or Safari on your Mac. So why bother? Well, thats a good question, especially if you dont have a lot of spare $6 bills lying around. But if you can afford it, Boxy provides several nice features missing in Inbox in your browser.
Boxys #1 advantage, in my opinion, is that it serves as your default email app, replacing Apple Mail. So if you click a mailto: url in another app, MacOS will launch Boxy rather than Mail. Is this yuuuge? Not, its not. If the link you clicked is in a web page youre viewing in your browser, and if youre already logged into your Google account, Chrome, at least, and possibly Safari, can open an Inbox or Gmail new-message window right there in the browser. So having Boxy as your default email client for MacOS matters mainly if the email link you clicked was in an app OTHER than your browser.
Boxy has a couple other very nice features, like the reader view, which expands the message content to full frame, eliminating the distracting UI stuff on the sides of the normal app screen. Theres also a true full-screen message composition window that I like a lot.
Ive given Boxy 4 stars rather than 5 simply because its not what I consider a must-have app. But I think it was worth my money and I think Im going to continue to use it.
Boxys not perfect.
The biggest problem has been noted by at least one other reviewer here in the App Store: Boxys prefs allow you to change the default font size, but only a little, and the largest font size is still a bit small to my eyes. For me its just on the edge of usability. The application prefs in Chrome give me greater control over fonts and font sizes, and those prefs affect fonts displayed in Inbox, so I find Inbox messages displayed in Chrome a little easier to read than the same messages displayed in Boxy. Hope Boxys developers allow at least one larger font size soon.
Someone else mentioned that Boxy feels sluggish. Not on my 2015 Macbook Pro. Now, if you have multiple Google email accounts (as I do), youll want to open each account in its own window. The default account-switching feature (accessed by typing Cntl-1, Cntl-2, etc) requires reloading the account youre switching to and this causes an annoying delay. Keeping each account in its own application window allows you to switch accounts much more quickly, as each account stays in the computers background memory. To open a second (third etc) account in its own window, hold down the option/alt key while selecting the account from the Accounts menu.