I listened to the lecture carefully. The technical content was explained in a friendly and easy-to-understand way, so it felt like a skilled senior was teaching me. Personally, I had a few regrets. First, the sound was too low and the sound quality was not good, so it was difficult to listen to the lecture. There was a lot of explanation about the API specifications, but I felt it was unnecessary for me. Instead, I wish there had been a more in-depth explanation of system design methodology and scaling. In such cases, what components can be considered, what are the advantages and disadvantages of each (although it was explained in Section 2), and what problems and improvements might arise during actual use. Despite this, it was a lecture that I learned a lot from. The instructor said that he would continue to update the lecture and lecture materials, and that he would improve the lecture quality by using a high-quality microphone in the future, so I look forward to it.