It started in 2011, when Lee left a Samsung-owned private hospital to start Viva Republica. “I started as a dentist, like all the other Asian children whose parents want their kids to be neurosurgeons or dentists,” he says with a laugh.

“When I was 29 or 30, I had no dream. I just wanted to be a famous dentist,” he remembers. But he soon grew restless with just helping people on an individual basis. “To create impact at scale, I quickly realized that I had to focus on technology.”

His push into entrepreneurship had a difficult start. He devoted 150 million won of savings—about $105,000—toward his new venture. “For the first five years, I failed eight times,” he says. He reels off a couple of what he calls “rubbish ideas”: social media, a voting app. 

A Bloomberg report from 2018 noted that, at one point, Lee had just 20,000 won ($14) in the bank, and was pleading with the families of employees to let them keep working without pay.

Then he found an idea that worked: a money transfer service. “Toss was another stupid idea, but we were crazy enough to do it, because we had nothing to lose,” he says with a smile. “And here we are.”

Almost 15 years after its founding in 2011, Toss is now part of a larger fintech “super app,” a single platform that combines banking, insurance, stock trading, and money transfer services. 

South Koreans have an average of five bank accounts and four credit cards—which means a lot of different financial accounts to juggle. Lee thinks that’s why Toss has proved so popular, as Koreans have “more occasions to check their finances.”

Viva Republica is now one of Korea’s most prominent startups, worth about $7 billion after a 2022 funding round. The company boasts backers like GIC, PayPal, and Qualcomm Ventures. Lee has also become one of South Korea’s newest billionaires, according to a 2021 estimate from Forbes.

The Toss platform claims to have close to 30 million registered users, which would be equal to around 60% of South Korea’s entire population. Over half of the company’s 25 million monthly active users visit the app at least 10 times a day. 

“Our monthly active user base is actually a little shy of that of Instagram [in Korea],” he boasts. 

Super-app success

Asia is covered in super apps, where platforms like Tencent’s WeChat include services like messaging, payments, food delivery, news, games, and more. Finance is a popular service for budding super apps, even for non-finance companies, with Singapore’s Grab and Sea, and Indonesia’s GoTo among Asian platforms with fintech divisions. 

Super apps keep users on a single platform, rather than sending them off to another company. That allows for cross-promotion, resource sharing, and other support between various services. It also makes it harder to switch to another platform: If everything you ever need is on one app, why would you try something else?

Yet super apps have not taken off in the West, even as the model wins fans like X owner Elon Musk, who hopes to turn his social media network into a financial services platform.

Lee’s theory is that super apps are a better fit for the Asian internet, which initially lacked much of the digital infrastructure that underpins U.S. startups. 

In the U.S., a new startup can rely on a plethora of other companies that provide supporting services. In Asia—even in wealthy countries like South Korea—those companies just don’t exist. That means a platform like Toss, or its more established Big Tech peers Naver and Kakao, had to build those services itself. 

“When we launched our flagship money transfer service, it was loved by so many users, so we were able to grow very fast. We quickly realized that all the other vertical sectors of finance were not covered by other players,” he explains. “There has been a huge void in the Korea market, so we were able to capture those opportunities.”

Startup milestones

Viva Republica hit a key milestone last year, when it reported its first annual profit since its founding over a decade ago. The company reported a net profit of 21.3 billion Korean won ($15 million) for 2024, compared with a 216.6 billion won ($152 million) loss the year before. Revenue also jumped 43% to hit 1.96 trillion won ($1.4 billion).

Lee says the first-ever profit is the result of a focus on growing revenue rather than building market share. “Unlike other fintech players, user growth doesn’t really correlate with revenue. Most of our revenue doesn’t come from users, but instead from our business customers,” attracted to Toss’s point-of-sale program, or its advertising opportunities. 

“For the next three to five years, it’s going to mostly be a story around acquiring more business customers,” he says.

Viva Republica’s profit also came from strong growth in Toss Securities, the platform’s stock trading service. Lee notes it’s the only service that charges users a fee, and contributes about 20% of the platform’s total revenue. 

He added that Toss Securities, after its launch in 2021, grew quickly owing to the Toss super app. 

“It took Robinhood two years to get 2 million securities accounts,” Lee says. “We achieved that in five days.”

Toss has higher penetration among younger Koreans, with as many as 90% of those in their twenties using the platform. Lee says that while there aren’t a lot of differences between Toss’s younger and older users, one major divergence is that newer generations are more open to investing in foreign stocks, primarily in the U.S. 

Now that Viva Republica has found a profitable business model, is the company on a path to a public debut, the next big milestone for a startup?

Lee says that Viva Republica plans to go public “in the near future,” but declined to give specific details on timing and location. 

According to local media, Viva Republica is considering a U.S. IPO, abandoning plans to list in South Korea late last year. The company reportedly believes that Korean equity markets won’t properly value a fintech platform like Toss. (Lee declined to share details when pressed.) 

Shares in competing fintech services KakaoBank and KakaoPay have lost around 70% and 80% of their value since their respective 2021 IPOs.

Market confidence

Korean equities often suffer from low valuations—sometimes dubbed the “Korea Discount.” Analysts blame the threat posed by nearby North Korea and poor corporate governance among the country’s chaebols, the massive conglomerates that dominate the economy. The country considered passing market reforms that would unlock value, similar to what was successfully pursued by its neighbor Japan. 

Yet reforms have stalled owing to a more pressing political crisis.

In December, then-President Yoon Suk Yeol tried to impose martial law. After widespread protests from the public and the opposition, Yoon withdrew his declaration just a few hours later.

Lawmakers quickly suspended and impeached Yoon, spurring months of political instability. Things are now starting to come to a close after the country’s Constitutional Court upheld Yoon’s impeachment, formally removing him from office—the second time a president has been removed in less than a decade. Korea will hold snap presidential elections in early June.

Still, Lee thinks the crisis shows South Korea’s strengths. “I’m gaining more confidence in the market,” he says. “Everything was done by the constitution, and the process was peaceful.

“This is the tipping point where we really need to focus on economic growth, not only from businessmen, but from politicians as well,” Lee continues. 

South Korea is grappling with disillusionment among the young, frustrated by high levels of debt, unaffordable housing, and more limited social mobility. That’s partly why many have turned to retail trading in stocks, or even more speculative assets like cryptocurrencies. 

The East Asian country, a major exporter, is also frantically negotiating with the U.S. to alleviate tariffs imposed by President Donald Trump, including 25% auto tariffs and 26% “reciprocal tariffs.” 

When asked whether uncertainty more broadly is affecting confidence among individual Koreans, Lee points to growth in Toss’s ads business last year as proof that the country’s economy is still strong. 

And he remains bullish on South Korea as an attractive market for anyone who wants to get into fintech. 

“Despite its limited population,” Lee says, “the Korean market is massive.”

This interview was conducted in collaboration with Fortune Korea.