Open-Source Scheduling Platform Cal.com to Close Core Code Over Generative AI Security Threats

Cal.com built its developer ecosystem around an open-source scheduling platform, with even the core code of its commercial edition available for external review. The company says generative AI allows attackers to scan, understand and exploit vulnerabilities more quickly, turning open-source transparency from an asset for collaboration into a risk to customer data and service security.

Cal.com recently announced that it would make the core code of its commercial edition closed-source, but did not disclose an exact effective date or any related financial figures. It also launched Cal.diy, a streamlined open-source project that preserves options for self-hosting and community participation. The company said AI has fundamentally changed the balance of risk in software security, prompting legal and governance debate over whether the move constitutes self-protection or a betrayal of open source.