I'm not a developer but I'm an IT/Technical Project Manager. I typically wear business casual. I interviewed at one place where the owner was in flip flops. So

I'm not a developer but I'm an IT/Technical Project Manager. I typically wear business casual. I interviewed at one place where the owner was in flip flops. So I felt dress up in slacks and a polo shirt. I interviewed at a very big financial institution so I wore a suit and I had one of my interviewers tell me, twice, that they DO NOT wear suit and ties to work.