Editors' note, June 23, 2014: This review has been updated to include features included in the latest version of Inbox by Gmail.
Inbox by Gmail (iOS|Android) is a step toward the future of intelligent email. It uses Google's smarts to organize your emails by topic, with the hope of making your inbox more streamlined. It does this by categorizing every email you receive, as either an important message that deserves space in your inbox, or as a less important update that can be lumped into a folder with other message like it.
Google introduced this concept for Gmail in 2013 with the tabbed inbox, where messages are automatically grouped into labels such as Promotions, Social, and Update. Inbox takes it further with a new design and more labels, all in the name of helping remove clutter from your email.
I've lived with Inbox for months now and it's completely replaced the regular Gmail app on my phone. Not only is it visually appealing, it's also full of features that help you find every message you need, when you need it. Despite all of its pluses, with Inbox you give up the control to organize your email using your own system. That won't jibe with everyone, but if you're willing to let Google take command, the app will reward you with smarter and cleaner inbox.
The app was once invite-only, but now it's free for anyone to use both on the Web and mobile. Unfortunately, you need to have a Google account, because it doesn't work with non-Gmail email accounts, like Yahoo or Exchange.
What it does differently
Most email services funnel all of your incoming messages into a single inbox, essentially a folder of unorganized emails in chronological order. You can often move emails into separate themed folders you create yourself, or set up filters to do this automatically.
Inbox seeks to organize each message you receive before it hits your inbox, automatically moving it to a folder (in this case called a bundle) without you moving it there. It categorizes every message you receive to see it if fits a theme, like travel or purchases, and then lumps it together with similar emails. This is what a filter does, but in this case, Google is creating that filter for you. Everything else that the app deems important but doesn't belong in a category shows up in your inbox as normal. This approach helps cut down on the number of loose messages in your inbox and helps you skim it more quickly.
Your new inbox
Influenced by Android Lollipop's Material design, the app is equal parts colorful, clean and cheerful. The best example appears when you empty your inbox and you're greeted with a bright blue screen and a yellow sun.
Your inbox is in chronological order, with messages from today at the top, followed by older emails. It's a mixture of individual messages which Gmail deems the most important, and bundles, which are folders of similar messages color-coded for easy skimming. Though I don't mind the chronological order, I'd like the option for other views, perhaps with the bundles at the top and individual messages below them or vice versa.
For each email, Inbox will show a the first few lines of text, and, where available, highlights from the message, including attached images, documents, or videos, helping give you some context. Some messages even have actionable links to track packages, view tickets or respond to calendar invites. All of this information is at your fingertips in your inbox, so you don't even have to open the message to see it, and I've found that to be one of the most helpful parts of the app.
At the bottom of the screen, there's a simple compose button. Tap it to start a new message, and you'll also get shortcuts to email the three people you've emailed with most in recent memory, and to create a new reminder (more on that later). All of the app's other tools, including settings, email labels, and the spam and trash folders, are stashed away in the slide-out menu.
Bundles of mail
If you're like me, you get a mixture of personal messages, promotional emails, account updates, and social alerts every day. Google is smart enough to recognize these emails and group them together in new themed labels called bundles.
The app comes with seven standard bundles; Trips, Purchases, Finance, Social, Updates, Forums and Promos. When a new email comes in that fits one of these themes, Inbox automatically sticks in that bundle, which then appears as a folder in your inbox. You can tap to open that folder and view the emails in it. This is designed to cut down on clutter, by keeping similar, likely less-important messages grouped together, so they don't get in the way of more important emails.