There were a couple of standard behavioral interviews with the CEO as well as the engineering lead, mostly looking at cultural fit and asking standard questions about your experience on your resume. The biggest part was coming up with a JIRA board and wireframe for a mock product (a healthcare dashboard that allowed users and doctors to access patient data and setup appointments). It was pretty open ended and mostly wanted to just see your creative process. While it wasn't super difficult, it did take a long time (the total interview process took almost two months, which led me to accepting a different offer).