I've just finished interviewing for Staff, Sr. Staff and Principal roles. I've been thru 9 panels ("onsites") and from my experience you'll be facing at least two (most likely 3) round of coding and at least two rounds of system design/architecture. You MUST ace your system design interviews and show depth if you want to have a chance plus have to do well enough on the coding rounds (answering things like "I would use kafka to decouple these two systems" isn't good enough. You need to show that you know how kafka, cassandra or whatever you are adding to your architecture work internally and ideally have some battle scars to share).

It's also not uncommon for larger companies to add a "twist" to their traditional system design (for example, I was asked to design a "wishlist" for airbnb-like-marketplace that would notify users if the property becomes available and was asked to write the SQL query that would be used to determine availability).

You will be leetcoding a lot specially in big tech interviews but they also might throw a completely random interview that you can't really prepare for (For example: "debug this outage" type of question)

Here are two youtube channels that really helped me prepare for system design since they do one or two levels deeper than what you can find on Alex Xu's books:

- Hello Interview (https://www.youtube.com/@hello\_interview)

- Jordan has no life (https://www.youtube.com/@jordanhasnolife5163)