Initial 30 min phone screening, then an hour long Javascript technical assessment on codingame.com (mostly about using Promises).
After that I had an hour long video interview with an engineering manager. We discussed a fair amount of technical things related to past jobs, but also spent a lot of time discussing my experience with agile development, being on a remote team, and what I thought my past successes and failures were as a developer.
Then I was given a longer take home assignment, which involved adding new functionality to a preexisting component (and making any changes/improvements that would be reasonable to point out in a code review). The new functionality required some refactoring of the existing code, but a total refactor was discouraged ... and overall I felt this was a good test of what actual development often entails. The assignment definitely required some clarification, but questions were encouraged, and the Collage CTO was quick to respond.
After that I had two hour long interviews with the founders (Kevin and Joey). Kevin's questions tended to be more technical, but also had a large behavioral focus (ability to work on a team, communicate, ask questions when confused, learn from mistakes). Joey's questions also had a large behavioral focus, and seemed directed at figuring whether or not I would be happy/successful working remotely, and a good fit at Collage generally.
Overall I enjoyed the experience, and was happy to accept an offer from them. I found video interviews to be more unnerving than in person ones (just because it's harder to read people via video, and sometimes audio/video lag makes conversation feel less natural). I would say that the interview process felt quite rigorous (like Collage was looking for something very specific at each stage, and if they did not find it you would not make it to the next step) ... I can see that rigorousness rubbing people the wrong way, but it had the opposite effect for me, since it made me more confident that they were being selective about their hires, and that if I did get an offer, that it would be a good fit for everyone involved.
Overall the process took a little over a month. I was told that the process could be accelerated if I needed them to make a decision faster, but I never took advantage of that offer.