Jan Koum

Jan Koum
Koum in 2014
Jan Koum
Born	24 2, 1976
Birthplace	Kyiv, Ukrainian SSR, Soviet Union
Nationality	American
Occupation	Businessman, computer programmer
Known for	Co-founding WhatsApp
Education	San Jose State University (did not complete)

Jan Borysovych Koum (born February 24, 1976) is a Ukrainian-born American billionaire businessman and computer programmer who co-founded WhatsApp, the widely used mobile messaging application. Born in Kyiv during the Soviet era, Koum immigrated to the United States at the age of sixteen and grew up in modest circumstances, at one point relying on food stamps to get by. Together with Brian Acton, a former colleague at Yahoo!, Koum founded WhatsApp in 2009, building it into one of the most popular communication platforms in the world. In February 2014, Facebook (now Meta Platforms) acquired WhatsApp for approximately US$19.3 billion, one of the largest technology acquisitions in history. Koum served as CEO of WhatsApp and as a member of Facebook's board of directors until 2018, when he departed the company amid reported disagreements over user data privacy and the introduction of advertising to the platform. His trajectory from a childhood shaped by the Soviet system to the pinnacle of Silicon Valley entrepreneurship has been the subject of extensive media coverage.

Early Life

Jan Koum was born on February 24, 1976, in Kyiv, in what was then the Ukrainian Soviet Socialist Republic of the Soviet Union. He grew up in a small village outside Kyiv, where his family lived in a home without hot water. Growing up under the Soviet regime had a formative impact on Koum, particularly regarding government surveillance and the lack of personal privacy. The experience of living in a society where private communications were routinely monitored by the state would later influence his strong stance on encryption and user privacy in the design of WhatsApp.

At the age of sixteen, in 1992, Koum immigrated to the United States with his mother and grandmother, settling in Mountain View, California. His father intended to join them but never made the move and remained in Ukraine. The transition to life in America was difficult. Koum and his mother struggled financially, and the family relied on government assistance, including food stamps, to make ends meet. His mother took work as a babysitter, while Koum himself swept the floor of a grocery store to help support the family.

Koum taught himself computer networking by purchasing manuals from a used bookstore and returning them when he was finished with them. He developed an early interest in computer programming and hacking, exploring network security as a teenager. By the age of eighteen, Koum had developed sufficient skills to attract the attention of security professionals. His mother was diagnosed with cancer, and she died in 2000. His father had died earlier, in 1997, while still in Ukraine.

Despite these hardships, Koum's early fascination with technology and networking laid the foundation for his later career. He has spoken about how the experience of growing up with scarcity and the absence of reliable communication tools shaped his desire to build a simple, accessible messaging platform.

Education

Koum enrolled at San Jose State University, where he studied mathematics and computer science. While a student there, he began working at Yahoo! as an infrastructure engineer in 1997, a position he obtained through connections he made in the security and hacking community. He ultimately did not complete his degree, leaving the university to focus on his career at Yahoo!, where he would spend nearly a decade.

Career

Yahoo!

Koum joined Yahoo! in 1997, working as an infrastructure engineer on the company's advertising system and other backend projects. It was during his time at Yahoo! that Koum met Brian Acton, a fellow engineer. The two developed a close working relationship and friendship that would later prove instrumental in the creation of WhatsApp.

Koum spent approximately nine years at Yahoo!, eventually growing disillusioned with the company's direction. Both Koum and Acton left Yahoo! in September 2007. After leaving Yahoo!, the two applied for engineering positions at Facebook and were both rejected. This rejection would become one of the more notable ironies in Silicon Valley history, given that Facebook would later acquire WhatsApp for billions of dollars.

Founding of WhatsApp

In January 2009, Koum purchased an iPhone and recognized the potential of the burgeoning App Store ecosystem. He conceived the idea for a simple application that would display status updates next to users' names in a phone's contact list — essentially allowing people to let others know what they were doing, such as being "at the gym" or "on a call." He chose the name "WhatsApp" as a play on the phrase "What's Up."

Koum incorporated WhatsApp Inc. on February 24, 2009 — his birthday — in California. He enlisted the help of a developer he had found through RentACoder, a freelance programming site, to build the initial iPhone application. The early version of WhatsApp was a status-update app rather than a messaging platform, and it initially struggled to gain traction.

However, when Apple introduced push notifications in June 2009, Koum realized that WhatsApp could be transformed into an instant messaging service. Users began pinging each other through the status update feature, effectively using it to communicate. Koum and Acton, who had been advising and helping with the project, shifted the application's focus to messaging. Acton provided early financial support and formally joined the company as a co-founder.

The app's growth was organic and rapid, driven by its simplicity, cross-platform functionality, and lack of advertising. Koum was emphatic about keeping the service free of ads and gimmicks, a principle rooted in his distaste for the advertising-driven business model he had experienced at Yahoo!. WhatsApp initially charged a nominal annual fee of US$0.99 after the first year of use, a model designed to sustain the company without resorting to advertising revenue.

WhatsApp grew at a remarkable pace, attracting hundreds of millions of users globally, with particular strength in international markets across Europe, Latin America, India, and Africa. The application's use of phone numbers rather than usernames simplified the sign-up process and mirrored the way people naturally communicated. By early 2014, WhatsApp had more than 450 million monthly active users and was adding roughly one million new users per day.

Koum maintained a small engineering team, keeping the company lean in contrast to the bloated headcounts of many Silicon Valley firms. He was known for disliking the label "entrepreneur" and preferred to think of himself as an engineer building a useful product.

Facebook Acquisition

On February 19, 2014, Facebook announced that it had reached an agreement to acquire WhatsApp for approximately US$19.3 billion — US$4 billion in cash, approximately US$12 billion in Facebook shares, and an additional US$3 billion in restricted stock units to be granted to WhatsApp's founders and employees. The deal was one of the largest technology acquisitions in history and drew widespread attention to Koum's personal story. The acquisition made Koum a multi-billionaire and elevated him into the ranks of the wealthiest individuals in the technology industry.

As part of the acquisition agreement, Koum joined Facebook's board of directors and continued to serve as CEO of WhatsApp, operating the messaging service as a largely independent unit within Facebook. Facebook CEO Mark Zuckerberg assured Koum and Acton that WhatsApp would be allowed to operate autonomously and that its commitment to user privacy would be maintained.

Koum reportedly chose to sign the acquisition papers at the building that formerly housed the Social Services office in Mountain View where he and his mother had once collected food stamps, a deliberate act that underscored how far he had come from his early days in the United States.

Departure from Facebook

Koum's tenure at Facebook grew increasingly contentious over time. By 2018, reports emerged of significant disagreements between Koum and Facebook's leadership over the direction of WhatsApp. According to The Washington Post, the clashes centered on Facebook's efforts to use WhatsApp's personal data for advertising purposes and to weaken the app's encryption protocols — issues that struck at the core of Koum's founding principles for the application.

In April 2018, Koum announced his decision to leave both WhatsApp and Facebook's board of directors. His departure followed that of co-founder Brian Acton, who had left the company in September 2017. Koum's exit was interpreted by many in the technology industry as a signal of the fundamental tensions between WhatsApp's privacy-centric philosophy and Facebook's data-driven advertising business model.

Following his departure, reports indicated that Koum continued to visit Facebook's offices periodically in order to vest remaining shares of Facebook stock, valued at an estimated US$450 million, as part of his original compensation package. In May 2018, Facebook announced a reshuffling of its board and executive structure following Koum's departure.

Personal Life

Koum is of Ukrainian Jewish heritage. His immigrant background and childhood experiences under the Soviet system have been frequently cited as motivating factors in his emphasis on privacy and accessible communication tools.

In 2014, Bloomberg reported that Koum had been involved in a domestic incident that resulted in a restraining order. Koum later apologized publicly for the incident.

Koum is known to have an interest in luxury yachts. In early 2025, his 328-foot superyacht Moonrise was listed for sale at approximately US$380 million, reportedly because Koum had commissioned a new, larger vessel. A legal dispute between Koum and French interior designer Rémi Tessier over the design work on two superyachts and a luxury property was reported in October 2025; the two parties reached a settlement in February 2026.

Philanthropy

Koum has been active in philanthropic endeavors, with a particular focus on education, scientific research, and causes related to the Jewish community and Israel.

The Koum Family Foundation has made significant contributions to academic institutions. In November 2025, Stanford University announced that the Foundation had endowed the Jan Koum Israel Studies Program at the Freeman Spogli Institute for International Studies, building on a successful pilot program. The endowment was notable in a period when some donors were reconsidering their support for academia over disagreements with university administrations.

Koum has also supported scientific infrastructure in Israel. The Jan Koum Center for Nanoscience and Nanotechnology at Tel Aviv University, designed by Michel Rémon & Associés, was completed in 2024. The facility, located at Israel's largest university, supports research in nanoscience and nanotechnology.

Koum has additionally been a donor to the American Israel Public Affairs Committee (AIPAC), at one point making what was reported as a record personal donation to the organization's campaign efforts.

Recognition

Koum's personal wealth, derived primarily from his ownership stake in WhatsApp and subsequent Facebook shares, has placed him consistently among the wealthiest individuals in the world. According to Forbes, he has been ranked among the richest Americans, appearing at number 44 on the Forbes 400 list.

In 2025, The Jerusalem Post included Koum in its listing of influential billionaires in the Jewish world, noting his impact through investment and philanthropy.

Koum's story — from an immigrant childhood marked by poverty and government surveillance to the creation of a messaging platform used by billions of people — has been widely covered in media profiles. His insistence on privacy, minimalism in product design, and rejection of advertising as a business model have been cited as defining characteristics of his approach to technology.

Legacy

WhatsApp, the product most closely associated with Koum, grew to serve over two billion users worldwide, becoming one of the most used communication applications in history. The platform's emphasis on end-to-end encryption, which Koum championed, set a standard for privacy in consumer messaging applications and influenced the broader technology industry's approach to user data protection.

Koum's personal narrative has become emblematic of the immigrant experience in Silicon Valley. His journey from reliance on food stamps to billionaire status through technology entrepreneurship has been referenced in discussions of immigration policy, economic mobility, and the American technology sector's capacity to attract global talent.

His departure from Facebook in 2018, driven by disagreements over data privacy and advertising, highlighted the tensions that can arise when privacy-focused companies are absorbed into larger corporations with different business models. The episode became a case study in the technology industry regarding the challenges of maintaining founding principles after an acquisition.

Through the Koum Family Foundation, Koum has established a philanthropic footprint in academia and scientific research, particularly through the endowed Israel Studies Program at Stanford University and the Jan Koum Center for Nanoscience and Nanotechnology at Tel Aviv University.