American Express Backend Engineer interview experience

I remember there being a lot of theory—less of a conversational coding vibe and more of explaining my thinking.

We started with Spring Boot, then moved into system design where I was asked to design any system I wanted. I also got hit with a classic coin change style problem. I solved it using a greedy approach, but I couldn’t get to the dynamic programming version the interviewer seemed to be looking for.

Overall it felt like the evaluation hinged on how well I could ground the technical concepts and match the expected approach for the algorithm, and I didn’t land it the way they wanted.