“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.”

Passionate employees

We believe in curiosity, kindness, and are driven by a strong sense of positive work culture. Our process is iterative, constantly learning from the things we try.

User accounts protected

Leading brands depend on Castle to protect over 500 million customers. We track and analyze large amounts of data in real-time to provide the best cohesive intelligence.

Office Locations

We operate globally from offices in San Francisco, Poland, and Sweden. We also embrace a supportive and open remote working culture.

Remote teams

Work without geographic boundaries

We welcome talent from all across the globe and also embrace a diverse and supportive remote working culture.

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Castle founded
in Malmo, Sweden


Founders move to the Bay Area to
participate in Y Combinator


Castle raises their Series A


Castle triples their team in
the next 12 months.

Castle founded in Malmo, Sweden

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.

Founders move to the Bay Area to
participate in Y Combinator

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.

Castle raises their Series A

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 triples their team
in the next 18 months.

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.

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