31. CORS Explained for System Design Interviews | Cross Origin Resource Sharing
CORS (Cross-Origin Resource Sharing) is one of the most misunderstood topics in web security and system design.
In this video, we explain why browsers enforce the Same-Origin Policy, how CORS actually works, what preflight requests are, and how misconfigurations can cause serious security issues.
This video is designed for software engineers preparing for system design interviews, backend interviews, and real-world API architecture. We also cover best practices, common mistakes, credentials handling, and how CORS is managed at API gateways and reverse proxies.
If you want a clear mental model of CORS instead of memorizing headers, this video is for you.