There are two moments when you want to hide your WordPress site: before launch, while you are still building, and during maintenance, when something is being fixed or redesigned. An under construction plugin shows visitors a simple page while you work behind it, logged in as normal.
The plugins look similar, but there is one detail that matters a lot, and most lists ignore: the HTTP status code the page sends to Google. Get it wrong during maintenance, and you can lose rankings. Compared the 6 best under construction WordPress plugins, plus how to use them without hurting SEO.