The interview process was a mess. I ended up with three 30 minutes phone screens with people in the US and an in house interview in Dublin with two interviewers.
The HR person who set up the interviews kept screwing up the details for the phone screen and the phone numbers they gave me didn't work. As well as that, on one technical phone screen the interviewer was completely unprepared and after a five minute chat he suggested another interview was set up a week later.
The interviews themselves were comically easy. More like a bit of a chat rather than anything testing. Technical interviews were really high level and nothing was covered in depth. The none technical interviews were limited to chatting about what was on my resume.
As an example of how easy the interviews were, one of the 30 minute phonescreens was supposed the be technical but we just chatted about things on my resume for 25 minutes and then the interviewer asked what a REST API was. I answered that it was an HTTP based API and mentioned CRUD (he didn't go into depth about what CRUD meant). That was the only technical part of the whole interview. The in house interviews weren't much more in depth than that.
Overall, the interview experience was pretty awful. HR couldn't figure out how to set up the interviews and the interviews themselves were far too easy. Anyone should be able to get a job at Mastercard with little effort.