I applied online in Nov 2021. It took about 3 weeks before I heard from a talent recruiter about setting up a phone screen. The phone screen asked very basic HR questions, followed by a few technical questions passed to them by the hiring manager.
Following the screening interview I interviewed with the hiring manager the next week. This was a standard interview. I described my experience and answered technical questions.
I was then invited to interview with 3 different engineers. The first was was technical (not really white boarding, however I was verbally coding at one point), the second was more team/cultural and the 3rd was project based.
Finally, I had a Cultural Interview where I was able to talk to an executive about Planet and ask any question that I had.
Overall the process took about 8 weeks (Winter Break/New Years was included).
To be honest after reading some of the experiences here I was quite concerned about being "ghosted", however I had a very wonderful experience. Everyone I spoke and worked with was very professional, and I was consistently updated throughout the process.