Klarna

Klarna was founded in Stockholm in 2005 by Sebastian Siemiatkowski, Niklas Adalberth and Victor Jacobsson, and Siemiatkowski still leads it as CEO. It started with pay-after-delivery invoices for online shoppers.

Today it is a global payments network and digital bank: flexible payments, cards and savings for more than 100 million active consumers and close to a million merchants in 26 countries. Its parent, Klarna Group plc, has been listed on the New York Stock Exchange since 2025.

About half of Klarna's people work in engineering and data, with Stockholm and Berlin as the largest hubs. Its core system was built in Erlang, the platform runs on AWS, and the company publishes open-source Erlang, Java and JavaScript projects on GitHub.