Great founders actually build.

So this question is: what are the biggest red flags for startup founders that you've interviewed?

There are many, many things that I look for in interviews, but one of the most important things I look for is the ability for the team to build the product themselves. Are they technical? Are they engineers? Are they scientists? Can they prototype this product? Is the demo built by them themselves?

The red flag that I look for is explanations that don't involve, "We're going to build it ourselves." Examples of that might be: we have hired an agency to do it for us, or we have hired outsourced engineers, someone else that is going to do it for us. Or, "We don't really need to build it because it's not needed to prove out this startup idea." Or, "Are we using some no-code solutions?"

That might be interesting, but at the end of the day, it probably isn't going to scale. All of these ideas are ignoring the fact that great startups are built by founders who can build prototypes themselves. That's what I look for, and all the things I mentioned are red flags to me.