I just took the first round interview today. The overall interview experience is very good and relaxing. Before the interview another two interviewees and I were invited to have lunch with the staff there (as normal what they do everyday). After lunch the interview went in order by: some generation questions, a coding practical, reasoning and math questions. The first two happened in different places with different interviewers and the last two were on computer. Generally speaking the difficulty was reasonable or easy and they didn't give you any pressure. There maybe two things to mention for incoming interviewers. For the coding practical you need to walk to another office of BrainLabs (which is only 2 minutes on walk from the one you have lunch). When I reach there I just asked the one I was pointed to find and did the practical. One thing needs to be mentioned is that the keyboard there is a UK style. As I always use a US style one I found it a bit weird to find some symbols (like # and "), which made me a bit nervous in the beginning. It maybe a good idea to practise using a UK keyboard for one or two hours before the interview if you're someone like me. Another thing I want to mention is that the reasoning question may be a bit time limited/difficult because of the English for non-native speakers. I found I spent too much time to read the questions and understand them precisely. The questions are not difficult after I understand them but I kind of felt like I was doing a English test more than reasoning. I also meet up some vocabulary which I forget/don't know so I think I didn't do well in this part. Maybe it's just my personal problem but I would like to tell you to expect this situation if you are a non-native speaker. But besides these two minor points I mentioned, the interview experience was very good and I really enjoy the environment there. I got my response two days after the interview saying that I didn't get into the second round as there are too many good interviewers. It was a bit disappointing as I think I did perfect well for the coding practical and math questions.

Two interviews at their London Office : the first involved giving a brief presentation on a topic of your choice, some maths and verbal reasoning tests, and a brief one-to-one interview. The second started with some small coding challenges, a longer coding exercise, a (pseudo-code) puzzle, and interviews with the heads of people operations. All quite demanding, but they're very good at making you feel relaxed and welcome.