I wore dark jeans, a button up shirt, and dark sneakers to my last startup interview and got an offer. But I also verified that was similar to their dress code

I wore dark jeans, a button up shirt, and dark sneakers to my last startup interview and got an offer. But I also verified that was similar to their dress code by asking on the initial interview call, too. If you want to err on the side of caution, step up to khakis and non-sneakers, but certainly no higher than that. I remember reading a general rule that you should dress one step up from the dress code where you're going to make a good first impression, but never more than that, otherwise you risk alienating your audience.