I was recommended for a position by a current, at the time, employee. I interviewed initially with my soon to be boss. I was scheduled to come back at a later date for a formal interview. This interview was with 4 current employees ranging from marketing, to engineering, to sales. It was mixed as 2 interviewers were very technical and the other 2 were more casual. This was a one day process that took about 3 hours. A couple of the interviewers were people that I didn't end up working with directly and were there to get a general idea about character and professionalism, the 2 casual interviewers. The other 2 interviewers got more into general knowledge about the company's products and understanding of responsibilities associated with the position. None of the questions were too specific as it is understood there would be a significant amount of training needed for any candidate, regardless of employment history or education. All interviews were 1 on 1in the employees office or a small conference room. The overall process was very casual and it was easy to tell by the interviewers attire what the atmosphere of the office would be like. I dressed nicely but could tell I would feel comfortable in jeans and a collared shirt. One of the interviewers consistently asked the most technical/difficult questions. She was very brief with the questions and wanted me to do all the talking which makes sense. She was very open at the end of the interview that she enjoyed our time and luckily she had the most pull out of the 4 interviewers regarding whether I would receive an offer or not. Ultimately, the decision came down to my future boss and I've had 4 good years since.