Seemingly overnight, Vero has burst into the internet zeitgeist — with the social network currently sitting in the top position on Apple’s App Store ranking of free apps.

The startup, which quietly launched the app in 2015, says it is nearing 1 million registered users. A major part of its appeal: Unlike Facebook, Twitter, Instagram or Snapchat, Vero does not have any advertising. “We made our business model subscription-based,” the company says in its manifesto, “making our users our customers, not advertisers.” That’s led observers to dub it “the anti-Facebook.”

Vero also touts its ability for users to fully control what they share (in four designations: close friends, friends, acquaintances, or anyone) with the ability to turn followers on or off. The app presents all the posts in the feed in chronological order.

“We don’t have algorithms that decide what you see,” said Vero co-founder and CEO Ayman Hariri. “You need to have the entire environment encourage a true social interaction.”

Hariri, a billionaire whose family operates one of the largest construction companies in Saudi Arabia, is bankrolling the company himself although he’s also brought in a few “friends and family” investors. His father was Lebanese prime minister Rafic Hariri, who was assassinated in 2005. Last year, Saudi Oger, the construction giant where Ayman Hariri had been deputy CEO, shut down “after years of mismanagement,” leaving thousands of workers unpaid and at least $3.5 billion in debt, according to a Bloomberg report.

The startup has a few Hollywood connections, including filmmaker Zack Snyder. Hariri, who has a computer science degree from Georgetown University, is a huge comic-book fan and owns one of the largest comic-book collections in the world (known as the “Impossible Collection”). The wealthy comics superfan met Snyder when he was directing “Batman v Superman: Dawn of Justice,” and Hariri had a few cameos in the movie.

After the two became friends, Snyder learned about Vero — and became a booster for the app. A rep for Snyder said he was attracted by the video and image quality of Vero, and that “he loves the clean interface, the ad-free environment, and the fact that there are no algorithms.”

Last September, Snyder posted his four-minute film “Snow Steam Iron” on Vero. The violent, noir-ish film, set “on the blood-stained streets of a seedy out-of-time New York City, also is available on Vero’s website (at vero.co/discover/zacksnyder).

Snyder last fall became a “brand ambassador” for Vero and the startup granted him an equity stake “as a thank-you for his support,” according to Hariri.

Vero also has a deal with DMC Film, the U.K. production company founded by actor Michael Fassbender, Daniel Emmerson and Conor McCaughan under which Vero is funding up-and-coming directors’ films. Other content deals include pacts with Max Joseph (MTV’s “Catfish”) for an exclusive documentary series “Charismatic Thinker”; actor Asim Chaudhry (BBC Three’s “People Just Do Nothing”) for his directorial debut with comedy “Love Pool”; and Condé Nast’s British GQ.

“We want Vero to be a place where creatives feel good about putting their content,” said Hariri.

It’s not totally clear why Vero (which means “true” in Latin and several Romance languages) has gone viral. Hariri said the growth has been organic, first attracting fans among cosplay enthusiasts and then professional photographers.

But Vero’s ascent could stall — because it’s not going to be a free app forever. The company is promising the first 1 million users who sign up free access for life. Hariri isn’t yet saying how much it’s going to charge for those beyond that. Once it puts up a paywall, however, Vero’s growth could peter out.

Hariri isn’t concerned. “It’s more about having people who are engaged and believe in it — and if that means less users, so be it. That’s not our metric of success,” he said.

Meanwhile, there’s a downside to Vero’s sudden popularity: The app is encountering technical issues and performance problems. The app was displaying sporadic “Server side service timeout” error messages Tuesday, and a notice on the startup’s site says, “We are experiencing higher than normal load. We are working to resume normal service as soon as possible.”

Those issues presumably can be resolved. But how long will Vero’s hype cycle last? While it may be benefiting from thousands of people wondering what the buzz is all about — or simply hoping to be among the first 1 million users who won’t have to pay — the jury is still out as to whether the “relationship-first social network” will have a lasting impact. The excitement could obviously wither once Vero starts charging users for the service.

“The target really is to make this incredibly easy for people to accept,” Hariri said. “It’s really not about creating this astronomically premium service. But at the end of the day, it has to be sustainable.” In addition to individual subscriptions, Vero charges a transaction fee to merchants when they sell products via the app’s e-commerce feature.

Hariri said Vero has about 30 employees, scattered across the globe in France, Germany, the U.K. and the U.S. “We don’t really have a formal office,” said Hariri, who now lives in Italy. As a legal entity, Vero is registered in New York.

At this point, Vero is not any threat to snipe users away from the major social platforms. Snyder, for example, currently has around 87,000 followers on Vero — compared with 619,000 on Twitter. But again, according to Hariri, achieving vast scale isn’t the endgame.

“We don’t have to get the entire world on this thing,” he said.