I was contacted by Helenja Wolfaardt after applying for the position on Wave's website.
My interview process was by far the most organized process I have been through at any tech company. Each step was quickly arranged by my recruiter and I knew what to generally expect from each step beforehand. Equally pleasantly, my interviewers were also prepared for each step of the interview, which made me feel they actually care about conducting a proper interview and take it seriously.
The process consisted of a take-home exercise, then three interviews with multiple technical members: one to go through my exercise and add features to it, one a system design that consisted of an entity relationship mapping exercise and then a more open ended distributed system design, and finally a more general interview focusing on technical and cultural fit.
The technical exercise takes about a day, but I didn't feel I had wasted my time as the interviewers had actually looked into the code and all of the first interview was spent on going through it, probing into decisions I had made and updating it to add additional functionality; so it did serve as an important piece of the interview.
In about a week after the interview, I was offered a position but not as a senior developer; after asking for feedback, a director of engineering provided a breakdown of my interview performance to explain their decision; I find the evaluation fair and objective.