I Interviewed for a Software Engineering Internship position. I talked to American Express at my university's career fair then scheduled to interview with them on campus a few days later. On campus interview was very easy (Do you know java, how do you make a class...) with a few logical questions. I was next asked to visit their 'Super Day' at the Phoenix Office. The Super Day event was much more difficult than any of the previous interviews and was pretty disorganized. There was a coding challenge which required dynamic programming (which no one completed in 30 minutes), additionally there was a 1 on 1 interview where the interviewer seemed bored out of their mind (similar easy java questions to on campus interview). Lastly there was a 'Team Hackerrank' where you and a random team of a few other people (also interviewing for the intern SWE position) with a question full of typos (Index starting at 0 at one line, starting at 1 on another, impossible to tell which was correct...), very few teams even understood the problem and my team's moderator actually got extremely upset at us. And yet they gave me an offer... Weird process.

lot of rounds of assessment, but quite efficient, there was a group interview, and final interview with the managers you are going to work with, overall good experience, took like less than a month