I applied online and they responded quite fast and scheduled the first call with an Engineering Manager. The interviewer was prepared and nice, knowing how to guide the process. We didn't move forward because Kantox was looking for someone around Barcelona area so they can have them on-site (my mistake, since the ad was specifying 1 day at the office) Overall I can recommend the company as they seem to have a good interview process in place.

The first of all, I have an interview with CTO (Daniel) for presentations. The second step, a technical test for develop a little ruby script. The third step, a talk with Lead of Developers and with RH And for exceptional situation I hav a fourth interview, this time with a team leader for more technical questions.