Editor's note: Enplug is one of Inc.'s 2015 30 Under 30. This year's readers' choice winner is ThinkLite.   

The week before Nanxi Liu graduated from Berkeley in 2012, she met with David Zhu, a friend of a friend, MIT dropout, and professional poker player. Zhu flew up from Los Angeles, and after 45 minutes, it was decided--they would start a company together. They just weren't sure what it would do.

On his flight back to L.A., Zhu met a junior in college named Zach Spitulski. Spitulski agreed to quit school for the as-yet-unknown company and convinced his roommate Alex Ross to ditch his job at Cisco. Navdeep Reddy, the fifth co-founder, knew Zhu from high school and joined the gang. Two weeks later, they all met in L.A. and Enplug was born. The team decided to build the standard operating system for digital billboards.

"Go with your gut"

"If you were to tell me this was going to happen, I wouldn't believe you," says Liu, Enplug's CEO. "But what makes us work so well together is that we all have this strong, go-with-your-gut feeling. I remember when we met one another for the first time in Alex and Zach's apartment and we all just talked, shook hands, and said, 'Well, it looks like we're going to start a company together. Let's figure out what we're going to build.'"

Enplug was founded in September 2012, after the group successfully went through Start Engine accelerator, in Los Angeles. With seed capital from Start Engine and AFSquare, the five founders rented a house in Bel Air, hired a couple of people, and decided to live and work in the house to save money. The result was a 24/7 culture.  The first 12 employees, all twentysomethings, build their desks from salvaged wood, work in their pajamas, and cook big dinners on the weekends. Some even got Enplug logo tattoos. 

"We are described as a cult," Liu says. "It's not too far off. When you join Enplug, it's not a job, it's a lifestyle. You eat, breathe, sleep Enplug everyday."

The billboard platform

The group decided to focus on digital signage--from jumbotrons in stadiums to TV displays in restaurants--because one unifying software platform didn't exist for the medium. Smart billboards and jumbotrons, like the ones in Times Square, require expensive custom development work because there is no universal operating system that can host apps and commands. Think about how a smartphone would work without an operating system: You'd have to program every action yourself. Enplug's operating system and app market help businesses get a display up and running, with whatever apps they want to use, faster and cheaper than before. "The technology for displays had not changed in decades, most were just running slideshows through PowerPoint," says Liu. "It made no sense to us, especially looking at the evolution of personal computers to smartphones. We thought it was archaic." 

The co-founders' goal was to make a unifying platform that could support every public display in the world. With a universal operating system and app marketplace, businesses could make displays support real-time social media for two-way communication with customers and passersby, and show engaging content. Enplug's platform is like Android or iOS, so developers build apps and release them into the Enplug app market, ranging from Facebook and Instagram to custom apps for a specific business. For example, many restaurants that use Enplug download the Waitlist app so patrons can see how long they have to wait for a table.  

Enplug's product is an HDMI device, pre-loaded with Enplug software, that can be plugged into a monitor, TV display, or jumbotron, and connected to Enplug's public cloud computing platform. Developers use Enplug's software development kit to build apps specifically for enterprise displays.

When the display is up and running, the customer can do things as simple as showing all the tweets, Facebook posts, Instagram pictures, and Yelp reviews about them on the screen in the lobby; hosting two-way conversations with customers sitting in a stadium; and displaying employee stats in the sales office. For the time being, Enplug charges $99 a month with all-you-can-download apps. Soon, the apps will be monetized.

Universal signage

With more than 450 clients, including BMW, Audi, Marriott, Radisson, Red Bull, Crossfit gyms, Dave & Buster's, Enplug's software is being used on public displays all over the U.S., Europe, Asia, Central America, and Africa. Liu says the most interesting places companies use Enplug's software are restaurants in Guam, corporate event spaces in Nigeria, and jumbo displays in concert venues in the Czech Republic and Slovakia.

In 2014, Enplug made $1.1 million in revenue and is predicting $8.3 million this year. The company has raised a total of $3.7 million in capital from Oaktree Capital and from individuals such as David Cohen of Interscope Records and Howard Marks of Start Engine.

Howard Marks says Liu is the most ambitious and talented entrepreneur out of the 60 who went through Start Engine in the past three years. "Their vision was to build the iOS for digital displays and they did it," says Marks. "Apple's iOS is the secret of their success and Enplug has the potential to do the same. Digital displays will be everywhere--in every office, restaurant, airport, and concert venue--and somebody has to power them and manage the software on that stuff. They are quietly building a billion-dollar industry."  

The major difference between Enplug and its competitors is that its software can be modified by businesses and developers through apps. Competitors in the space have closed systems--they own the screens, the software, and the network--meaning that businesses cannot customize the display themselves. With Enplug, businesses can buy a cheap monitor, buy Enplug's device, and customize the display with apps. 

The co-founders, minus Zhu, who left Enplug last year, have yet to take a salary, but they did finally move the company to a proper office in Culver City in 2014 after surpassing 30 employees -- too many to fit into a house.

"We want to build something that is so transformative that it will define an industry and an era of technology," Liu says. "It sounds cheesy, but we are aiming to build a company worth several billion dollars."