First stage is Phone call is about 1 hour and the second stage is a offline technical tests (48 hours deadline). Tech tests is awkward. Personally, I have up to 6 hours to work on it within a 48 hours, if you have kids, you may know what I mean. To implement a bank transfer service, from API to DB with all tests covered, you must be very familiar with SpringBoot family so that you can spent more time on the logic. By the way, the reviewer seemed not to read your comments or readme. So, your solution need to be in commercial standard to pass their review. Anyway, here is my feedback I remembered: 1. No exception handler ( I clarified that in readme it is an improvements can be done if time allows) 2. Used synchronized without concurrency requirement ( Isn't it common sense to handle two transfer requests at the same time? I have a test to prove the concurrent issues, they seemed didn't look.) 3. No validation on bank account (I have a validation on the source account balance and return an error response. Also has test covered. Again, there are surely more validation can be improved if time allows, I put them in the readme but seemed to be ignored) So, in brief, 10X interview experience is not good. Tech test costs your time but you don't get a chance to discuss it. Reviewer is not open mind and doesn't care your comments or readme. It gives me the impression that they is looking for the people doing work same as them and don't open mind to other people's opinions.