Internal transfers are close to mandatory in many cases. Veterans are strongly encouraged to move every 2-3 years to cross-polinate engineering knowledge and culture.
For someone at a senior level (Amazon SDE III/Facebook IC5), an internal transfer is at most a perfunctory whiteboard session, and often just a conversation - you already have passed an interview loop to get into the company, after all, and have an easily-verifiable track record thereafter.
For someone at a senior level (Amazon SDE III/Facebook IC5), an internal transfer is at most a perfunctory whiteboard session, and often just a conversation - you already have passed an interview loop to get into the company, after all, and have an easily-verifiable track record thereafter.