I applied online at the start of March and received an email asking me to participate in a Hacker Rank challenge 2 weeks later. There was 1 hour to complete 2 questions. The questions we easy in hindsight but were presented in a very wordy way, they revolved around string manipulation and some algorithms. By April I was assigned a recruiter, who contacted me via email, to organize a phone screen. The Phone screen was with an engineer that worked in the team I was interviewing for and there was 1 main coding question and a lot of opportunity to ask questions about Twitter and the role. Another 2 weeks and then an offer to come for an onsite for "1-on-1"s on one of 3 days that they were running for the new grad season. For me there were 3 interviews, although others had 4 or 5 depending on how many teams were interested in them. All three were coding questions, the first centered around css and javascript, the second a string/algorithm one and the final was a OO design. I was notified about an offer by then end of that week since I went on the last day of the onsite interviews. The initial offer was amazing and I didn't feel compelled to negotiate.