I was initially contacted by a recruitment agency, who after an initial talk sent me a set of online tests which I passed, I had a phone interview afterwards with the leader which I also passed, and a few days later I went to their offices for the final interview. I thought it was a very interesting place, the interviewers were extremely knowledgeable.

First you will do a phone call and then an online C test. It is annoying and does not proof any good knowledge of C, however managers know that (but still keep it because they're probably lazy to look for something better) and even if you fail it you can pass to the next step. Then you will be invited to a face to face interview, which is really easy.