“Who in their right mind would build an email client?” Gentry Underwood asked himself nearly two years ago. At the time, it was a fact of life that email sucked. Nobody cared about rethinking email. So he built an email client.
At launch, Mailbox generated so much hype that nearly 1 million people joined a wait list to get access to it. The app promised a simple, lightning-fast experience that made emailing feel like texting. And it introduced “snooze,” a feature that let you put off emails until later. “For a long time email was this area of tech that you didn’t touch, which was old and stodgy and not worth spending time on,” says Underwood. “Mailbox demonstrated that that wasn’t the case.”
In the ensuing years new email apps like Hop, Mail Pilot, AirMail, CloudMagic, and Boxer seemingly launched every week. Even Google started paying attention to its email app on iOS. Mailbox hasn’t convinced everyone to jump on board, only rarely cracking the top 50 in the App Store’s productivity category, but it nevertheless kicked off a trend where both developers and consumers seemed to agree that while email couldn’t be killed, it could possibly be fixed.
As Gmail hits its 10th anniversary, Mailbox has been quietly preparing its next big thing — a system that automatically clears out bothersome threads, spam, and emails you don’t need until later. And there’s no wait list to try it out.

Today, Mailbox is announcing three things: an Android app launching today, a beta version of its Mac app, and "Auto-swipe," a feature that intelligently predicts which messages you’re going to archive, and which messages you don’t want to address for a while.
Mailbox’s Android and Mac apps are refined but predictable adaptations of the company’s iOS apps, but Auto-swipe is something entirely new — a learning system that’s part Gmail Mute, part machine-learning algorithm. Let’s say you’re included in an office email chain welcoming a new employee. It’s probably the right thing to do to say hello to your new colleague, but at that point, who needs to see each and every reply? Most people would archive the thread, and then sigh as it returned to their inbox with each and every reply-all.


Without a tool like Gmail’s "mute" or Outlook’s "ignore," maintaining any semblance of inbox order is impossible. But these tools are blunt instruments buried inside menus, far outside the reach of most people. The question people want answered is simple: how do I make this email thread or this sender go away? It could be an office email, or spam, or a newsletter, or a coupon from your favorite store. It could be something you want to unsubscribe from, but aren't exactly sure where to click. Auto-swipe aims to address all of these scenarios — in human terms.
The question people want answered is simple: how do I make this email thread or this sender go away?
In the latest version of Mailbox, when that pesky office email chain pops back into your inbox for the second time, a green bubble will appear in its subject line. If you tap it, the app asks if you want to archive the thread permanently. Tapping again makes the thread fly out of your inbox, along with any other threads that fit the bill.
If you want to manually archive any thread for good before waiting on Mailbox’s suggestion, you can open it up, and then tap and hold on the archive button. Similarly, if you keep snoozing your Groupon emails until after work, or your club soccer emails until Friday afternoons, Mailbox will notice your actions and offer to do them for you for incoming emails of those kinds. Or you can manually invoke action by tapping and holding on the snooze button. The goal is to remove all the clutter you didn’t even know existed — the messages that you assumed needed to stay in your inbox because they showed no signs of stopping.
Auto-swipe bases its assumptions on the sender, recipient, and subject line of your emails, along with how you interact with messages. "The app very quietly makes suggestions about improving what it does," says Underwood, "and when you choose one, you just made Mailbox smarter." A new section inside Mailbox’s settings page lists all the rules you’ve created, and allows you to delete any rules you no longer find useful. The page also lists recent emails that have been automatically dealt with, like that office email chain. The end result is, hopefully, a lot fewer emails cluttering your inbox every day. "I’ve been blown away by how many messages this thing is catching for me," says Underwood. "We’ve reset the system several times during testing, and the most recent system we’re running is three days old but has already saved me 100 messages."

"Auto-swipe" sounds vague and non-descript, but so does the idea of server-side mail compression to make your emails feel as tiny as texts. The virtue of Mailbox thus far has been rooted in bringing complex ideas to the masses in comprehensible ways. Concordantly, perhaps the most valuable aspect of Auto-swipe is that it turns mute into a function anyone can use. Most users might not even realize that Auto-swipe has a name — they’ll just tap and hold on the archive button inside annoying threads and know that they’re going away for good. "It doesn’t look like much," says Underwood. "It’s just some email subjects, senders, and recipients with little colored labels. It’s almost not there — it’s very respectful of whatever you’re trying to do."
"It’s almost not there — it’s very respectful of whatever you’re trying to do."
Letting Auto-swipe come up with rules on its own might not appeal to everyone, just like Mailbox’s GTD-centric snooze button, which lets you put off emails until later. But luckily, you can treat Mailbox’s archive button as a mute button if you so choose. And in comparison to other utilities it actually feels faster. It takes the same or fewer number of taps to mute a message in Mailbox than in Gmail or Outlook, although Mailbox doesn’t (yet) let you mute multiple messages at a time. In this regard the app may not feel as powerful as Gmail, beloved by many for its organizational colored labels, but it’s certainly more balanced. It’s hard to think of many more places where Gmail beats Mailbox — especially if you’re a fan of slick, native applications.


Mailbox for Mac completes a family of native, cross-platform mail apps — a feat most big companies often fail to achieve. "I spent a lot of time hacking Mail.app to create a somewhat similar experience to Mailbox," Underwood says. "We made a decision early on to build a native client because that’s what we wanted. This is a tool we live in for such a huge chunk of our lives, so we really wanted it to be great." Mailbox for Mac isn’t actually much different from the company’s mobile app. It even lets you swipe to archive just like you can on iOS and Android. While Mailbox for iPhone came out first, Underwood and his team envision each of your devices as an equal platform deserving a native experience — something few companies today seem to believe. In the company’s tests, archiving a message on Mac made it disappear from Mailbox on iPhone instantaneously — a feature no IMAP email client can boast.
When the app launches in the coming weeks, the company’s mobile apps will be updated to let you snooze messages not just to tomorrow, but back to your computer. The feature could come in handy on trips, for example, when you want to clear out most of your inbox until you get back to your desk so you can focus on more urgent messages while you’re traveling.
All this automation sounds a bit scary, which is why Mailbox spent so long developing and tweaking the feature before launching it. "Gmail’s Priority Inbox, Sanebox, and Unroll.me try to make these decisions automatically, and therefore need to be totally reliable," Underwood says. But can it ever be 100 percent reliable? "The short answer is no," Underwood says. "Some messages that you don’t read often, you still might want to see in your inbox."
"I don’t think [email] will ever completely go away," Underwood says. "From a data perspective, it’s actually being used more. People receive more email year over year. Some people replace mail with more dedicated tools, but mail is the universal collaboration platform." Google seems to agree: the company recently began testing a series of interesting ideas inside Gmail that seem inspired by apps like Mailbox. But advanced features in Gmail and other email solutions like Boomerang are too complicated for most users. Like Apple, Mailbox has proven its ability to artfully revitalize old ideas and make them almost invisible to users. In doing so, Underwood says, people might actually use them. "What we uncovered was in some sense bigger than Mailbox itself."