Informal screening call to start with, easy going chat about experience and interests, one or two STAR type questions to help things along if needed. If that goes well then you get a take home assignment. The assignment can be completed in any language however there are project templates available in ruby and javascript. It's an easy enough task and there are some tips to help, the main focus seems to be on clean code and understanding. If that goes well the final stage before offer is a more in-depth technical interview where you're asked to talk through your solution and then a bit about projects you worked on in more technical detail.