The whole process took about a month, but that's because I requested about a week of prep time for each stage of my interview. I had three on-site interviews in total. My screening was on-site because I live very close to HQ. I also did a third-round interview because my feedback for the second round was somewhat mixed.

Overall, I was very pleased with the whole interview experience. The internal recruiter was very friendly and helpful in assisting me with prep, and also very communicative of each step and process that they were going through. I was never kept in the dark.

Almost every interviewer was super friendly and knowledgeable. I had mixed feelings before the interview, but after the whole process, I was convinced that Facebook is a great place to work.

No single question stood out as most difficult or unexpected. Just know your algorithms and data structures, as well as your specific domain knowledge.