Your question is Scale WebSockets for Millions. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
How would you scale WebSockets for millions of users? (connection management, how many connections a server can handle, what limits scalability, load balancing, memory, CPU, TLS overhead)
Asked in the Round 1 - DSA stage. Backend scalability discussion before coding; open-ended, thought process evaluated.