Content Sync is a Gatsby Cloud feature for improving the Preview experience for content authors.
When content authors press “Open Preview” in their CMS, Content Sync routes them to the correct URL. It helps them understand the status of previews, so they know when their content is ready to view and otherwise if there were any build errors. It does this by redirecting to a “waiting room” page which displays a loading state while the content preview builds. Once the build is complete, the author is redirected to the correct page on the frontend of the Gatsby Preview site automatically.
Content Sync will route users to the correct page even when pressing “Open Preview” from within a nested node which has no associated top-level page.
If the build for the preview fails or if no page is created that contains the content being previewed, Content Sync UI will display an error message.
To learn more about how Content Sync works under the hood and how to make sure your plugin can support Content Sync, see the conceptual guide in the open source docs here.