I had a vague fear that social login and OAuth2 would be as complex and vast as Spring Security, so I hadn't been able to touch them until now. However, through this lecture, I was able to clearly experience the sequence of request flows leading from the authorization code to the access token and finally to the user information. Furthermore, by writing code for both the frontend and backend, I was able to gain a solid understanding of the scope of responsibility for each area and the potential security issues. This lecture is concise yet dense regarding social login and JWT. Thank you for the high-quality lecture.