I love Paylocity's interview process! You start off by talking with an internal recruiter a few times (I had Sam who was great!) so that they can get a feel for your personality and your current skills and work environment and so you can get a feel for what Paylocity is all about as well.
In most companies that I've interviewed with, the next step is to have a phone screening with an engineer to get a more solid understanding of what you know followed by a very brief assigned coding exercise to submit which is then followed by onsite interviews by several engineers and whiteboard coding.
HOWEVER, Paylocity does NOT do that. Instead, the recruiter will send you a very open-ended assignment to build an app to submit. This is fantastic and absolutely gives you the opportunity to showcase what you know in a very real-world type of way with a substantive amount of code instead a super small sample in the very specific exercises that most companies have you complete.
Once you complete the app, you'll meet online with a few engineers who will do an extensive code review of your app with you. The goals of this process are pretty obvious: Can you explain what you did in your app and why you did it that way instead of another? If you had more time what would you do? Can you graciously accept feedback and criticism? Will you be easy to work with or a difficult personality? What part of the stack are your strengths and weaknesses?
These aren't necessarily questions that will be asked (some will), but questions that the interviewers will be trying to answer for themselves about you.
The engineers will then make their recommendations to a hiring board about your fate. You must receive a unanimous vote from all interviewers to be hired.
The app really gives you a chance to shine instead of filling out some small stub-method like other companies have you do.