First you have chat with recruiter.
Then you have: interview with Engineering Manager (1h), Live coding session (1h30min), System Design (1h30min), Cultural Fit interview (1h - 1h30min)
During whole process you get updates from recruiter. That's good
Generally I wouldnt recommend Primer because I was getting positive feedbacks through the whole process, even at the end recruiter told me that feedbacks in the system look very good, just they need to wrap up conclusion on some meeting together. Then, after 10 days waiting I got feedback that I'm not good enough for SWE III, that i can get SWE II if I'm willing to wait for the ongoing swe II interviews to finish, so that they can see if i'm the best :)
They told me what was bad, but to be honest, it was all c**p from my pov. serious company doesnt behave like this. I shouldnt have gotten green light after each interview for next round, just to be told that I'm not that level after 10 days of waiting. It would be fine If they told that they have better fit than me, but bot that I'm not good enough.
Also, after all rounds I asked if I would be match for senior role if Primer had an open role, recruiter was really insulted by that question. Literally his answer: 'We were transparent about salary range. You will get your offer probably and you decide, take it or leave it. Non-negotiable'
After that I waited for 10 days and didnt get an offer. Very negative experience