First recruiter phone screen, then 45 minutes on-site technical interview followed by a 4 rounds technical interview loop. Interview process is good however it appears the interviewers are more focused on coding fast and coding without bugs. It is a test for memorization skills instead of actual algorithms knowledge and the candidate's ability to solve a real engineering problem. They are looking for canned solution, any out-of-box idea would get rejected. I'd say the facebook hiring criteria would prefer younger coders who are just out of college and who had been exercised simple algorithms codings for a year or so. Leetcode.com is its bible. Experienced engineer may not be favored if you don't have time to sweep the coding exercises.