Jan Koum

Jan Koum was born in 1976 in a village near Kyiv, then part of the Soviet Union, in a house without hot running water. His family emigrated to Mountain View, California, in 1992 when he was sixteen, settling into a small government-subsidised apartment; his mother took in babysitting work and, for a period, the family relied on food stamps while his father remained behind and never joined them.

Koum worked as a janitor at a grocery store to help with household expenses while attending school, and taught himself computer programming and networking largely from secondhand manuals rather than formal coursework, later attending San Jose State University without completing a degree. He got a job testing security at Yahoo, where he met Brian Acton, and the two worked there together for roughly a decade.

In 2009, after both left Yahoo and Koum was turned down for a job at Facebook, he began building a simple messaging app that would show a status update rather than clutter phones with notifications; it evolved quickly into WhatsApp, a text messaging service that let people avoid the per-text charges then common on mobile networks, particularly valuable for users outside the United States. Acton joined him as co-founder shortly after.

The app grew to hundreds of millions of users largely through word of mouth before Facebook bought it in 2014 for roughly nineteen billion dollars, one of the largest acquisitions of a company with almost no advertising revenue at the time. Koum served on Facebook's board before resigning in 2018 over disagreements about data privacy and encryption policy, later donating substantial sums to organisations supporting refugees and privacy advocacy.