"We need to serve 1TB of data. How would you do it?" Start there. Let the candidate walk through the problem. Ask questions, and introduce hypothetical limitat

"We need to serve 1TB of data. How would you do it?" Start there. Let the candidate walk through the problem. Ask questions, and introduce hypothetical limitations. "We need to display the data in a table on a webpage." (frontend) ... "We need an API that can query the data." (backend) ... "We need to sort the data." (discuss algos) It's not that hard to find people's strengths, and make sure you're hiring qualified folks.