That’s where the roster of tech stars comes in. Ruchi Sanghvi and Aditya Agarwal came from Facebook, where Sanghvi was the social network’s first female engineer. She’s probably best known for cocreating the News Feed. The two left Facebook in 2010. Last year both joined Dropbox, which had just acquired their startup (along with cofounding a company, the pair are also husband and wife). Sanghvi now leads operations at Dropbox, and Agarwal heads engineering.

Another top engineer putting in nights and weekends at Dropbox’s vast San Francisco loft is Guido van Rossum, inventor of Python, the programming language released in the late ’80s and on which Dropbox and countless other pieces of software are built. Van Rossum’s decision to leave Google for Dropbox late last year put the tech world on notice about the caliber of talent putting its faith in the young company’s potential for success.

He describes life at Dropbox as “just a bunch of really smart kids doing cool stuff.” He says they remind him of himself when he was one of those kids hacking away with like-minded geeks two decades ago to perfect Python. “Dropbox has done an amazing job building a product that everyone knows and everyone uses and everyone loves,” he says. (Well, 200 million someones, anyway.) At the same time, he says, he was drawn by the prospect of fending off challenges from much larger competitors—such as his former employer—by helping Dropbox grow as quickly as possible: “The urgency was very compelling.”

To grow at a pace that keeps Dropbox a credible contender, the company believes it must focus on becoming the default file system for a multiscreen world. But that will happen only if it manages to convince third-party developers to incorporate Dropbox into their apps. And not just a few. Pervasive data is only pervasive if you can truly access that data from every app, from social networks to email to games to word processors to web browsers. Ultimately that demand will have to come from Dropbox users. Right now the company is working to seed that demand through events like the DBX developers conference.

In the meantime, Dropbox must keep rivals large and small at bay. Among startups, a leading nemesis is the similarly named Box, which was founded shortly before Dropbox. Box has since turned its focus away from the consumer market that Dropbox courts to pursue business customers, a segment Dropbox is also eagerly chasing. Box says it has more than 120,000 companies on board, including 92 percent of the Fortune 500. Dropbox says it has millions of businesses signed up.

Much more worrisome for Dropbox are Google’s Drive, Apple’s iCloud, and Microsoft’s SkyDrive, sync-and-store products that do a lot of what Dropbox does, at least on the surface. These big tech companies can subsidize their consumer cloud offerings with the money they make from other lines of business in a way that the startups can’t. That could make it difficult, even impossible, to compete.

But that’s not the right way to look at the competitive landscape, Dropbox backers say. The company isn’t selling server space. It’s selling a service. And when it comes to service—continuous improvements, overall experience—Dropbox is beating the behemoths. Google, for example, took about seven years to launch Drive, which was finally released to the world last year. “I wouldn’t expect them to quickly iterate from there,” deadpans Facebook cofounder and Dropbox investor Dustin Moskovitz.

Meanwhile, Dropbox keeps attracting new users, thanks to a product that, as the blazing neon sign at one end of its office reads, “just works.” Compare that claim to, for instance, Apple’s clunky iCloud, which works mostly to keep your data locked inside Apple’s tidy ecosystem of hardware and software. Dropbox is counting on such restrictiveness to trip up its big competitors, who have less incentive to offer a service that works well across all devices and formats.

Dropbox is proudly agnostic. This is the gambit that has kept the company from taking the easy path to big returns and selling out to any one of the tech giants. By staying independent, it can market its usefulness to the widest possible swath of users. And the more users who come to depend on Dropbox, the more leverage Dropbox will have to say to Apple, Google, Microsoft, Amazon, and Facebook: Open your gates to us or our millions of users may go elsewhere.

The arc of Dropbox’s success so far gives its founders reason to hope they really can attain that kind of leverage. “If we don’t build a company as influential as Google or Facebook, then we failed,” Ferdowsi says. “I’m, like, perpetually stressed, honestly.” That feeling of pressure can only grow as people tell him his ambitions aren’t crazy.

In the future as imagined by Dropbox, the gadgets are dumb, the features are smart, and data trumps devices. And that data doesn’t just follow us on our laptops, phones, and tablets. It’s in our cars, our fridges, our watches. Dropbox may or may not ultimately build that future. But it’s hard to imagine that someone won’t. Maybe someday a service like Dropbox will be more like a public utility, basic infrastructure for pervasive data that would be invisible, assumed, inevitable.

Until that day, Houston plans to keep holding on to the rocket he launched five years ago. Sitting in a Dropbox conference room as engineers on scooters zip along the long, narrow office’s concrete floors, he remembers the first time he had that feeling, when a beta-launch demo video on Digg sent the waiting list for the service spiking from 5,000 to 75,000 in just one day.

“That was when I was like, oh my God, this thing could be huge. It was sort of like this out-of-body experience,” Houston says. “It was really exciting. You feel the engines rumbling underneath you and it was like, here we go!” Into the clouds.

Correction appended [2:37 P.M. PST/9/17]: A previous version of this story incorrectly quoted Dropbox cofounder Drew Houston saying “anybody with nipples” instead of “anybody with a pulse.”