Server-side speed
Aside from its GTD-inspired features, Mailbox is much faster than Apple Mail, Sparrow, and especially Gmail for iOS at fetching and sending emails. Unlike most email clients, Mailbox servers check your email accounts and securely compress emails in advance before pushing them down to you. "The problem with third-party mail clients on iOS is that they only get access to your [internet connection] while they’re running," Underwood says. "If you’re creating a mail client and want to use IMAP, you have to initiate that laborious connection every time users launch the app." Not only that, but Mailbox scrapes away every part of a message except its body text, which greatly diminishes the size of an email. "If you open some email, 10 percent is relevant to you," Underwood says. "We separate the wheat from the chaff, pull out what matters, and leave the rest on Gmail." Combining intelligent scraping with compressing messages means that pushing dozens of emails to you only uses an SMS-like amount of data, Underwood claims.
Mailbox scrapes away every part of a message except its body text, greatly diminishing its size
But Mailbox’s scraping algorithm isn’t perfect. It only works in English so far, since Mailbox servers use cues like "On Wed, Feb 6, 2013 at 12:02 PM, Thomas Houston wrote:" as signs to cut anything afterwards. The scraping engine also fails sometimes, since every mail client and service sends messages a little bit different. Aside from adding more languages, Underwood has big aspirations for the way Mailbox displays emails. "We should be able to detect more and more over time what the valuable content of an email is," he says. "If it’s a receipt, why not make it look like receipt, and if it’s a tracking shipment from UPS, we can display it as such and keep it up to date. We can get smarter and better because we have this opportunity ahead of when your phone gets a message to do the heavy lifting (server-side)."
A technical challenge
Processing hundreds of thousands of emails per day is an enormous task, and means that if you download the app today, you’ll likely see a number representing your place on the waitlist to get in. "There’s no fail whale for email," Underwood says. ‘We need to stay up. It’s a big responsibility, and it keeps us up at night." If you multiply an initial 10,000 users by an average of 100 messages per person per day, and then multiply that number by the amount of activities required for an email to reach your phone, you’re approaching ten million activities on the system per day, Underwood says. So far, 250,000 people are in line to use Mailbox. "These are some serious data challenges," Underwood says. "Nobody knows how long it will take to get everybody in, but it will look like an exponential curve."
Having Mailbox process your emails sounds scary, and Underwood and his team understand that. "At the highest level, our interests are very much aligned with the people whose mail we’re checking," Underwood says. "If you have a privacy issue, that’s a major downer for you as an individual." Mailbox uses the same OAuth2 authentication protocols apps like Sanebox and Boomerang use to check Gmail without ever storing a copy of your password. "We’ve gone to Google and asked if we’re doing everything by the book, and we are," he says, "but just like Google, we are susceptible to hacking." The company has done everything it can to keep servers highly encrypted and safe. "Nobody on our team can read your emails," Underwood says.