Mock Interviews

Pramp - Practice live technical interviews for free!! You're paired up with another individual and halfway through, switch interviewer/interviewee roles. It's pair-programming interview practice. As the interviewer you are given the problem, hints, as well as the answer in pseudocode 24 hours before the interview, so that you can guide and be able to give constructive feedback on how interviewee can do better. The interviewee just sees the problem.

Leet Code - Premium subscribers can select mock interviews specific to companies, like Google or Facebook. Otherwise, it's free if you just want the practice.