“We’re on a mission to make consumer security simple and invisible. We enable developers to build uncompromising security in the easiest and most flexible way possible.”

Housed out of a 90 square foot closet (The rent was $50 a month, including fiber broadband), Castle became the third company founded by the two developers and friends, Johan and Sebastian, who at the time had been working on tech together for over 10 years.

On the third attempt Castle was finally accepted to Y Combinator and the founders moved to Mountain View. There they went through the accelerator and eventually raise their seed round from investors like First Round Capital and yes, Y Combinator.

After growing the team and reaching their first million dollars in annual revenue, Castle raised their Series A from Index Ventures, which allowed them to quickly triple the team and set up their first dedicated offices.

Castle continues to expand the team from three offices in San Francisco, Krakow, and Malmö, as well as fully remote, and now protects over 500 million end-users worldwide.