My interview process started in October 2015 when I submitted my resume. After about 2 weeks I was contacted via email to complete the code challenge and answer a questionnaire. Since I was abroad for 2 weeks I had to ask for an extension which was approved. The code challenge had to be written in either Java or C#. Showing your OO design skills is important here and writing some tests. I suggest you spend some time seriously thinking and answering the questionnaire as it will be used again for the in person interview. I submitted the two items in mid November. I didn't hear back from them and reached out after two weeks. They got back to me in the beginning of December for a phone interview and scheduled one a week before Christmas. The phone interview was a basic cultural interview about who I am, my previous experiences and what I think about social justice (basically a shorter version of the non technical in person interview). At the end of the phone interview they told me that they would like to fly me to Chicago for a 2 day in-person interview in mid January. They booked my flight and hotel. The interview is on Thursday and Friday. They fly you in on Wednesday. They send an email a couple days before with details of what the two days will be like. On Thursday, there was a presentation, Q&A and a office walkthrough of Thoughtworks. Then we had to take a Wonderlic Test which was 12 minutes long with 50 questions. The ThoughtWorks logic test was next. There are 11 problems and you have an hour to complete it. I was only able to complete 10 of them. The last part of the interview for that day was a group assignment. We were given specs and told to build a house with the lowest cost for puggles. There was a time limit of 25 minutes. They watched us talk it out and draw the house. After 25 minutes we had to present our solution. That was it for the first day. On Friday, we were each given a personalized schedule and assigned rooms where the interviews would be held. We then had an hour to prepare a STEM presentation to be given during the non pair programming technical interview. I had the pair programming interview first for 1.5 hours. I worked with two other Thoughtworkers on my laptop to refactor my code from the code challenge. Here they asked me a lot of questions about why I designed my program the way I did and how I would improve on it. I really enjoyed this part of the interview. I also asked a lot of questions about OO and programming questions in general. Next up was the 2nd technical interview for 1 hour. I did my 5 minute presentation and they asked me questions. Then they went through my resume and asked me about OO and general programming questions. It was then time for lunch and we sat in the open area chatting and eating. After lunch, I had the non technical interview. This is where they learn about who you are and what your views of the world are. They had general questions about how I would handle certain work situations and thought provoking questions like does democracy really work. Most of it is based on what you wrote on the questionnaire. Overall I enjoyed the interview. It really does take a lot out of you and by the end of the second day I was pretty burnt out. Every person I met was friendly and made us feel as comfortable as possible. Try not to be too nervous and relax. Take time to go through your code and questionnaire before the interview. Try to drink something warm before/during the interview. It definitely helps calm your nerves.