The interview process was approximately 2 months, somewhat lengthy, but I think a lot of what played a factor was the holidays at the end of the year, as well as my being gone for a whole week in January - which they were very understanding of.
Overall - they did a fantastic job of keeping me apprised of updates. My HR point of contact was fantastic, always making sure to stay in contact, and going as far as letting me know their personal cell-phone number in case if I had any questions.
At first, I was contacted via LinkedIn who mentioned Affirm was looking to expand in Chicago, and their was a potential opportunity there. From there I was connected with my HR point of contact actually at Affirm.
I had 3 phone interviews (one with HR, one with the hiring manager, and then one with a member of the team (Integrations Engineer to discuss technical concepts).
After moving to the final round from there, they flew me to San Francisco for a half day on-site where we went over basic technical trouble-shooting exercises, technical concepts, client relationship building, and finally a mock presentation for a project kick-off.