The process was straightforward. I responded to an internship posting and also got an employee referral by an alumnus from my degree program. Twitter HR responded and over the course of two months scheduled 1 phone interview and 2 Bluejeans interviews with managers in the department. At the end I had a final Bluejeans interview with the head of the department. The mix of questions ranged from the hypothetical to the practical, and were geared towards the type of work I would be doing in that Twitter department.