My overall experience interviewing at Twitter is generally positive. Everyone I talked to seemed really excited about working at Twitter, and I got the sense that Twitter has many of the things I was looking for in a company; e.g. transparency (within the company), fast-moving environment, focus on employee learning, exciting place to work. The actual interview process was somewhat prolonged. I was initially put in touch with a recruiter in April via a friend's referral; it took a few weeks until I started actually interviewing (beginning with an online coding question and then a couple of phone interviews, all of which were very doable). It took several days to a week to get feedback after each of the initial interviewing milestones. To the recruiter's credit, I was always asked whether I had any timing issues, and I get the feeling that things could have been sped up if I really needed them to be. I eventually got to the on-site interview stage (in July), which had about 5-6 interviews. As one might expect, this was kind of exhausting, but I found myself actually liking this format, mainly because failing 1 interview out of 5 or 6 is much better than failing 1 interview out of 3 or 4. The majority of these interviews involved coding questions, although there was one that tested system design and one that tested *nix fundamentals. The coding questions were generally what you'd expect from any other premier tech company; there's not really much insight I can provide here. I received an offer about a week or two after the interview.