I applied online. The process took 4 weeks. I just had 5 stages of interviews with Kraken during a period of a bit over 1 month.

• 1st stage: A video chat with a technical recruiter. He basically talked about my experience, about crypto, etc. I found the first stage a bit confusing, because he clearly didn't have a proper plan in place. First he asked me the difference between a bit and a byte... er... what?... then, he was prepared to ask me a few PHP questions, but I stopped him right there and said: "You may ask me some PHP questions, but I've never done any PHP ever, so I won't be able to answer..." The recruiter said that's fine. Absolutely terrible. Why ask those questions to a React developer? I ended the interview, thinking this was a complete amateur process, since the questions were all over the place.
• 2nd stage: A technical interview, mainly an hour with just technical questions.
• 3rd stage: A technical challenge. Without going into much detail, and not exposing, at all, what they ask, there's a section regarding the API that mentions something like we have the choice of writing the API server, create a fake API, mock it, use an external service, etc. As a candidate applying for a frontend position, this tells me that the relevant part is, of course, the frontend application. The fact that we could mock it, or even use an external service, indicates that you are not responsible for that API. Either way, I chose to do it myself, using Node.js.
• 4th stage: A review of the technical challenge. I did a run-through of my implementation and answered all of their questions. One of the developers asked me why I didn't embed the styles (I was using Sass). I said that I chose to use a BEM approach that, of course, promotes re-usability, etc. The other developer commended me on that choice. I passed all of these 4 stages.
• 5th stage: An interview with the VP of Technology and another senior dev. The senior dev asked me a few more questions regarding React, which I answered pretty easily. The VP of Technology was simply amazing, with an excellent attitude and overall world-class, and asked more high-level questions. The senior developer, after 40 minutes, and with just 5 minutes to go, made a criticism regarding my backend implementation that I totally acknowledged (not a big deal, and something that would have been covered if I were applying for a backend position).

In the end, the recruiter sent me an email stating I was rejected for 2 reasons:

• The current hire on the team will need a more in-depth understanding of the advanced features of Sass. I honestly think that they simply didn't know what BEM was. Search "What is BEM and why you should use it".
• A security concern on the backend. My focus was on the frontend. Why did I pass to the 5th stage if I had already supposedly passed the review and evaluation of my technical assignment? What if I had chosen to just mock the API? I think that would have been a much better choice, apparently. What if I had chosen to use an external service? How would you evaluate an external service? It's important that you understand that the phrasing is misleading. And senior developer, why waste everyone's time if, in the end, you already had in mind that the security concern you pointed out would be enough to get me rejected?

The rejection came via a standard email with those 2 points, and that was it. I spent more than 1 month, took time away from holidays, and the outcome was this. Ironically enough, I spotted a security-related concern in the kraken.com website, which I shared with the recruiter with details and steps to fix it. He never replied back, which I thought was a big lack of professionalism. Absolutely terrible. No Kraken, I won't apply back again if I see an opportunity that sparks my interest. What you did was simply waste my time. I honestly feel it was an unfair outcome. That was my experience.

TL;DR: I went to the 5th stage... then: "You know that little something that's only relevant to something you did on the 3rd stage, a good few weeks ago? Yeah... we didn't like that, sorry."

The difference between a bit and a byte.