Their recruiter contacted me; he was professional and helpful. After an introduction and two phone interviews (one technical, one with a hiring manager), I went to their office in downtown SF for an onsite interview. I was looking for a machine learning position, but I interviewed for a data scientist position instead. I had four interviews, two data science, and two coding interviews.
Overall, the technical interview process was straightforward and simple. Their data scientist engineers are smart, energetic, but lightweight on statistics/math. When I start talking about the statistical theory or even regularization, they looked lost. Their approach to machine learning was mostly based on trial and error rather than analysis. They would try different algorithms from sklearn and plug it to panda hoping it would work.
I was completely shocked by their cultural fit interview which happened during their lunch time.
The interview was with 3 of their engineers from data science team. Their data scientist team completely lacked vision. The first red flag appeared when I started asked questions about Affirm's business and finances. How the company is managing the risks? How the data science team is achieving the Affirm's vision? Where affirm would be in the next 5 years? These are the typical questions I asked every company. I was shocked when they answered half of my questions with "we cannot tell you that, that is secret". They had no background on finance, which I found shocking for a company with a modern banking mission. The final nail in the coffin was when I asked how they validate their business model or measure success, expecting an objective answer from a "data scientist", instead I got the "dude, look around. We have the coolest office".
Finally, during the interview I was working a tsv file that had a lot of user information. Even if the user info was hashed/mangled, they exposed a recruit with the type of the data they were collecting from their users, which is unethical and violates the user's privacy.