I finished the course yesterday and today. I used to have doubts about the direction of my development when developing API designs or controllers with Spring, so I lacked confidence, but through studying the HTTP specs this time, I learned the core. Also, even when I always looked at the network in the developer tool, I didn't understand the header information, so I used to vaguely deal with errors. This lecture was very satisfying just by being able to see and interpret error codes while developing. The lectures were short and short, taking less than 10 minutes on average, so it was easy to listen to and it was good. I'm sorry that I didn't have anything to change while writing the course review... ㅋㅋㅋ It's a good lecture that I would like to recommend to beginners in the web and those who are developing but are vague about web development.