Completely depends on the company. Don't go jeans and t-shirt, but for most startup/tech companies suit and tie is too far the other direction. Long-sleeve but

Completely depends on the company. Don't go jeans and t-shirt, but for most startup/tech companies suit and tie is too far the other direction. Long-sleeve button-down and slacks probably works in most cases, but again for startups/tech companies you probably want them to be more cool than corporate. No pleated khakis or high-starch polyester shirts. It shouldn't really matter that much since the whole reason developers don't dress up to work is because it's not the dress that matters, it's the work. In reality it matters anyway, at least at many companies. Try to find photos of their team at work on their website, dress a bit nicer than that.