So, you want to knock on doors for your favorite presidential candidate? Traditionally, you'd have to formally sign up as a volunteer, meet with a member of the campaign staff, undergo a training session, and get a list of names and a stack of flyers before you could be on your way.

The Bernie Sanders campaign just condensed that process into a matter of seconds, with a new canvassing app that makes volunteering in the field as easy as downloading the app, logging in, and getting started.

The app, called Field the Bern, launched in the Apple app store Monday and was, fittingly, developed by a merry band of grassroots volunteers affiliated with the groups Feel the Bern and Coders for Sanders. Now, the Sanders team has absorbed the app as its own, enabling it to funnel the data collected on Field the Bern directly into the campaign's main voter database.

The new tool is only the latest example of how Sanders' young, tech savvy supporter base has raised his profile throughout this campaign. On platforms like Reddit, they've successfully built the largest subreddit for any presidential campaign so far. They've built tools like Debate with Bernie that let followers automatically retweet Sanders on debate nights. On volunteer-built sites like FeeltheBern.org, they've helped break down Sanders' policy platforms to make them easier for the general public to understand.

With Field the Bern, they're now helping online activists take their work to the streets, which, says Sanders digital director Kenneth Pennington, is still the most crucial part of any campaign.

"Although we’re running a very modern campaign, and we do have a lot of people out there coding amazing projects for Bernie," he says, "we still believe in the traditional knock on the door to get the message out."

In early voting states like Iowa, the Sanders campaign has a robust field staff to do that work. According to Daniela Perdomo, the creator of FeeltheBern.org who helped conceive of this app, the purpose of the tool is to enable the Sanders team to run a ground game even in states where it doesn't have a major staff presence.

"There’s no point in disincentivizing people in places like New York from getting information now, just because the campaign isn’t yet in the state of New York," says Perdomo.

On the app, supporters get access to information on how to canvass, including sample scripts and information on Sanders' platforms. Volunteers can see where other canvassers have been, but they're free to knock on any door they choose. As they move from home to home, they can enter an address and input information on people's names, party affiliations, and how interested or disinterested they are in voting for Sanders. That information gets sent straight to the Sanders campaign. Volunteers get five points for every door they knock on and 10 points for every piece of information they update, so they can see how they rank against other volunteers.

There are, of course, risks associated with encouraging people to represent a campaign without formal training and supervision, but Pennington says the rewards are far greater. Led by chief engineer Josh Smith, volunteers spent a total of 1,400 hours working on the app, a job that Perdomo estimates would have cost the campaign $250,000 had they hired a firm to build it.1

"We're taking advantage of real, distributed organizing, and giving volunteers the responsibility and leadership ability we know they can handle," Pennington says, "We can do so much more because we’re empowering these volunteers."

1Update: 3:00 pm EST 01/05/16 An earlier version of his story miscalculated Perdomo's estimate of the total cost of the project.