Started with a recruiter screen and a 45 min tech/screening round with 2 coding questions on string and array logic- more like LC mediums. The onsite was 4 rounds back to back: systems/linux, coding, design, and behavioral. The linux round was definitely the hardest part. It started with a basic troubleshooting scenario about a slow server and went deep into kernel internals, syscalls, and network retransmits. You really need to know your tools like tcpdump and strace. Design was about building a messaging platform at scale, and behavioral was standard as usual. For prep I brushed up on linux fundamentals, LC mediums for coding, and also went through some reddit posts. Also did a mock on Prepfully with an actual Meta PE. That turned out to be a lifesaver because it helped me tighten up my networking answers which were a bit weak. The systems round is a total filter I believe so you have to know your Linux internals inside out. Overall it's a fair process but very technical.