Doesn't a separate design interview turn into too long a stage among all selection stages?

A separate system design interview can increase the overall selection time, but it is justified if the goal is to deeply assess the candidate's architectural skills. For middle and middle+ specialists, it is important to test the ability to design scalable, fault-tolerant solutions.

To avoid prolonging the process, you can:

• Clearly regulate the time for the design interview (e.g., 45-60 minutes).
• Focus on key aspects, avoiding unnecessary details.
• Conduct preliminary screening to invite only suitable candidates for the design interview.

Thus, a separate stage for design is a balance between depth of assessment and process efficiency.