Johan Brissmyr

Johan Brissmyr

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11 Ways to Pinpoint a User's True Location

11 Ways to Pinpoint a User's True Location

Hi 👋 – I'm the founder of Castle, a developer-first fraud prevention platform that helps you automatically collect and analyze a user’s location based on location indicators–one of many features...

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9 Device Fingerprinting Solutions for Developers

9 Device Fingerprinting Solutions for Developers

As the availability of unique IPs and user agents wanes and cookie reliability remains half-baked at best, device fingerprinting has emerged as a serious contender in the battle against online fraud a...

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7 Proxy Piercing Techniques: What Works in 2023?

7 Proxy Piercing Techniques: What Works in 2023?

Introduction With the rise of online tracking, proxy and VPN services have become a popular way to protect people's privacy. However, these digital shields also provide an opportunity for bad act...

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Swiftly identify fraud rings with instant link analysis
Product •

Swiftly identify fraud rings with instant link analysis

Castle is a real-time rules engine designed to manage fraud and risk across all touchpoints, including onboarding, login, payment, and content sharing experiences. We're excited to announce a new...

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We’ve raised $9.2 million led by Index Ventures
Company •

We’ve raised $9.2 million led by Index Ventures

In 2015, Sebastian and I created Castle with a simple vision. We saw that it was increasingly difficult for companies to access their online accounts and keep their users safe. We also saw that consum...