Classic process: phone interview w/ a bunch of general Java questions then onsite.
Before the interview, I already had seen a bunch of red flags on Glassdoor, but did not pay attention too much (recent reviews + a bunch of consecutive reviews in May from current employees to improve their rating). My overall experience is pretty bad.
The interview process was really scripted (so scripted, some of them asked me to solve the same puzzle twice). Even if you can feel the experience of senior people, their knowledge about Android architecture and patterns are not that good (don't know RxJava for instance). It turns out they use a bunch of third parties into their app and the most interesting algorithms are not home made.
On 3 onsite interviews, 2 went well. The last one was a disaster. The interviewer was not capable of understanding solutions other than his, and was really confused by any other way of tackling a problem. At the end, when I asked about the next step in their process, he told me it was the final one that day, and they usually do not need any onsite to make a decision. He then said in my case, they will make a decision quickly.
Unfortunately for him, it turned out they wanted me to come back onsite. Sounds like someone made his mind too quickly... I then politely accepted to come back but they took a week to just get back to me, whereas I was already passing final interviews with other companies, meanwhile. Hence, I aborted the process. I eventually figured out their office manager is in charge of the lobby/snacks/catering and people team too...
TL;DR - If you want to work for a social network, go work for Facebook. Engineering will be better.