can you play with foil cards in tournaments

can you use foils in magic tournaments?

Yes, but check with your judge first. Because foils tend to bend easier than regular cards, this can often make them easy to spot in a deck. If, for example, all your lands are foil and nothing else, that'll look very dodgy to a judge. So check with the judge first to make sure they're alright. Sleeves help.

What if you have all foils?
I like to be stylish. (:

As long as they're not marked in any way, it should be fine.