3 rounds of interview with 6 people in overall. First round with the team leader and one of the agents, second round was a trial day with a different agent, and the third was supposed to be via google hangouts, but something went wrong, so I had three people interviewing me there in person. The process took three weeks altogether, but I got the offer two days after the 3rd / final round of the interview.
The interviews had two types of questions; first all regarding your previous experience and why would you like to change and work for Transferwise, second type was "out of the box" questions where they thoroughly try to analyze your character and see how you think and would you be a good fit for the team and the company.