Yes, spaghetti noodles are vegan. They are made from semolina flour, water, and salt. There is no dairy or egg in their production. This is the case for most spaghetti noodles, but it is common to find people adding eggs and egg yolks when making homemade noodles because their fat helps make the dough more stretchy. If you look to achieve that same result, add a tablespoon or two of olive oil before kneading.