How to get hired at L6+ in Big Tech?

Well, the first step is to apply. If you have 10+ years of experience, they would probably give you a shot for L6. ~15 engineers is roughly Big Tech L6 scope as well.

In terms of passing the interview, that's an entirely different story. I recommend these:

• "Does FAANG hire at Staff+ levels?" - Go through all the linked resources in my response there
• "How does the Meta interview work?"
• [Taro Top 10] Breaking Into FAANG

So the tricky thing for you is that you're now in M-Track (M = management). L6+ engineers are crucial to Big Tech (we hired them extremely carefully at Meta), so I imagine most hiring managers will be skeptical of your ability to switch back to an IC role.

If you want to get hired at L6 instead of M1 (equivalent engineering manager role by Meta leveling), I recommend being a hands-on Engineering Director. Take part in production issue post-mortems, review system design docs, and maybe even review some code here and there. This hands-on experience will be crucial in the system design portion of the interview.

If you're interviewing with Google/Meta, you will probably need to do data structures and algorithms (DSA) as well. I recommend this masterclass for that: [Masterclass] How To Ace Your Big Tech Interview - Data Structures And Algorithms

You should decide whether you want an Individual Contributor (IC) role or an Engineering Manager (EM) role. The prep for these is going to be very different.

In this macro-environment, many companies want you to start as an IC before transitioning to management. This is especially true for middle management (M1), but if you can make a claim to being a senior manager, you may be safe on the manager ladder.

For more senior roles (like the ones you're vying for), referrals are even more important. Leverage your network, esp if someone from your startup went on to FAANG.