The preview is not updating or looks wrong
What the preview shows, how to refresh it, and what to tell the builder when a page looks wrong.
Last updated September 17, 2026
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Check the build finished
The preview shows the latest compiled build. While the builder is working, it says Building your app, and the preview refreshes when the build completes. If a build failed, the builder fixes it in the same turn; see "The build failed".
Refresh it
Press the refresh icon above the preview. Do this after editing data in the Database tab, which the app may not have re-read yet.
Look at the right width
Use the desktop, tablet and phone buttons above the preview. A layout can be right at one width and wrong at another.
Tell the builder what you see
Say which page, which element, and what is wrong: on the schedule page, the Book button does nothing. Your browser reports errors from the preview to the builder automatically, and after each build the platform opens the app itself and hands the builder anything the pages threw, so it usually already has the details. It can also take its own screenshot of the page to check.
An embedded map or video shows an error in the preview
The preview is sandboxed for your safety, and some third-party embeds complain about that. The published app is not sandboxed, so the embed works there. Publish, or open the published address, to see it.
Signed in as you
The preview signs you in as an admin of your own app, so you see admin-only pages that a visitor will not. To see the visitor's view, open the published address in a private window, or ask the builder to show you the signed-out view.