@samejr has helpfully created a ToastPopover UI element that is ready to use for this issue in the toast-ui branch. What we'd like to happen is if there is a JSON parsing error we should show this an error that displays the parsing error message in a toast (using the above UI component). You would need to update the createFromUrl.ts action function to catch JSON parsing errors and redirect back to the root "/" path and store the toast message in a cookie (see this remix example for an example.