Standard 2 interview screening + 5 interview if you pass the screening. You can prepare for the interview by looking up resources online - Meta has a fairly consistent process. The only reason for me writing this report is that despite the recruiters' professionalism throughout, it was quite galling that after a long process and even after "passing" the hiring bar, I was told they were going to pause the role (though my 'pass' is good for 12 months). I'll post an update if I have one.

The loop at Meta has definitely evolved recently. The initial phone screen was standard algorithms. However, the virtual onsite was much more practical than I expected. They still have the architecture and behavioral rounds, but they also included a live coding and debugging session. They want to see if you can actually navigate a messy codebase under time pressure, not just memorize optimal solutions on a blank screen.