It was great to be able to gain good knowledge through a solid payment service! Personally, data consistency is a very important part of payment service, so it was great to be able to acquire various technologies so that it is not missed. It would have been better if it had been done in Java, and the focus was on a 'solid payment service', but there were some difficult parts about introducing spring webflux. I think it would have been difficult for students who do not know spring webflux to approach it.