Hugo shortcodes are reusable template fragments that can be embedded in Markdown content. They bridge the gap between Markdown’s intentional simplicity and the richer, more structured HTML that publishing sites often need — figure captions, callout boxes, video embeds, custom alert blocks, styled pull quotes — without requiring authors to write raw HTML in their content files. Hugo ships with a small set of built-in shortcodes and provides a straightforward system for building your own.