Symbols is a powerful feature in Sketch that allows you to reuse elements easily across Artboards and Pages.
A Symbol is made up of two parts: a “master”, which takes the appearance of an Artboard—and an “instance”, which is a flattened representation of the master.
As you create a Symbol, you can automatically send the Symbol Artboard, or master to a separate page. When you make a change to a Symbol’s master, the changes are applied to all Artboards and Pages in your document. In addition, each instance of a Symbol can be customized with overrides. In the video below, we’ve created a quick tutorial on how you can use Symbols to save time and improve your workflow.
A Symbol instance is a single layer that mirrors the content from its master. In the Layer List it is displayed with a purple icon with syncing arrows . A common example of a Symbol is an element that is re-used throughout your design such as buttons, or a cell in a table view.
Not only that, Symbol instances can be individually resized, and you can apply resizing constraints to layers inside the Symbol to determine how they should behave when resizing.