Will visitors see version A flash before version B loads? (Essential CRO Split AB Testing app)

Usually not, but it can happen.

The app chooses the version in the visitor's browser. When a visitor is assigned to the other version, the app sends them to it right away (a template test adds ?view= to the URL, a theme test switches the theme). On slow connections, especially on mobile, the original page can show for a moment before the switch.

To keep this as short as possible:

• Make sure the app embed is turned on.
• Avoid heavy scripts that load before the page.

Returning visitors already have their version saved, so the switch is quicker for them. The app doesn't change your canonical tag. For template tests it normally still points to the original URL.