As data sovereignty regulations tighten and cloud costs escalate, modern enterprises are rethinking their Identity and Access Management (IAM) strategies. While proprietary Identity-as-a-Service (IDaaS) providers like Auth0 and AWS Cognito offer convenience, they come with vendor lock-in and unpredictable pricing. This comprehensive guide explores why self-hosting Casdoor—an open-source, powerful IAM platform—is becoming the preferred architectural choice for data-sensitive businesses.