Stackbit allows you to share a live preview of any changes made to your site without requiring that you publish them first. When viewing a realtime preview of any page, you can copy and share a link to a live preview. To do so, click the "copy" button as seen below.
Anyone with the link will be able to view the preview. The preview will include any changes you've already made and any changes that you continue to make. They will see content as it updates, just as you do. However, they will not be able to make changes to the content.