Cal.com Shifts to Closed Source for Enhanced Security Amid AI Advancements

When we founded Cal.com, open source was at the heart of our mission. However, the rapid evolution of AI technology has forced us to reconsider this approach. Today, AI can efficiently scan open source codebases for vulnerabilities, making it akin to handing over blueprints to potential attackers. This shift in the security landscape has led us to the tough decision to transition to a closed source model to better protect our users' data.

AI's ability to identify and exploit vulnerabilities at unprecedented speeds has been demonstrated by recent incidents, such as the discovery of a 27-year-old flaw in the BSD kernel. The emergence of AI-driven security startups further complicates the situation, as they offer varying assessments of vulnerabilities, leaving us without a reliable standard for security.

Despite this change, our commitment to the open source community remains strong. We are releasing Cal.diy, a version of our codebase under the MIT license, allowing developers and enthusiasts to continue exploring and experimenting with our technology. This version, while diverged from our production code, ensures that an open source option remains available.

The decision to close our source code was not made lightly, but it is necessary to safeguard our application and customer data. We are hopeful that as the security landscape evolves, we might return to our open source roots. For now, our priority is the safety and security of our users.