Fiserv Software Developer Engineer interview questions

Chill interview process, 2-3 rounds talking to principal engineer for that team and recruiters, sometimes people have to talk to PMs too. Very friendly and conversational interview and felt like the guy had a genuine interest in getting to know me as a person and for my skills.

Did 1 30min prescreening and then 1hr long behavioral/technical interview with a project manager. Prescreening was very basic and chill. Talked about experience and tried to gauge interest. Interview with PM was also very chill and cordial. Went a little deeper into my experience. He did trivial Q&As like: Is JS single threaded or multi-threaded? Maybe throwing out some feelers to see how deep conversation can potentially get.