The main difference is in the type of wrapper. Egg roll wrappers are made of wheat and eggs and is thicker than a spring roll wrapper. When an egg roll is cooked, the wrapper gets golden and the skin gets these little bubbles under the skin that are crispy but a little chewy at the same time.   Spring rolls wrappers are a thin pastry sheet made of wheat flour, salt, vegetable oil and water.  Unlike egg rolls which are thicker and are made from flour and eggs, spring rolls are thinner and get extra crispy when fried, baked or air fried. When it is cooked the wrapper gets flaky and the layers of the pastry melt in your mouth. They are not chewy but instead very crispy.