Note: this project is no longer maintained / usable beyond Craft CMS 3.2 – deprecated in favour of headless previews.
Sites that make use of the Element API may not benefit from Craft's preview features if they're not making use of templating. This plugin adds a button to the Entry editing screen which links to a preview URL with
?version=$id parameters so your backend can look up content from the correct place.
It's your responsibility to write the backend code to fetch these revisions/drafts, but this plugin should allow you to give users a way to preview content directly from the editing screen.
To install this plugin, search for its package name on the Plugin Store and click “Install”.