PluginRx

Simple Maintenance Redirect allows site administrators to enable maintenance mode by redirecting visitors to one of your specified pages (without header and footer) or an external URL instead of complicating things with all kinds of confusing settings. Logged-in administrators can still access the site normally, ensuring a seamless workflow while updates are made.
Features:
<ul>
<li>Custom Maintenance Page: Redirects visitors to a selected WordPress page while the site is in maintenance mode.</li>
<li>Maintenance Page Modifications: Automatically hides the header and footer on the maintenance page and adds a <code>maintenance-mode</code> class to the body element for further customization.</li>
<li>External Redirect Option: Redirect to an external URL instead of a WordPress page if needed.</li>
<li>Admin Bypass: Logged-in administrators can continue working on the site without redirection.</li>
<li>Developer Hook: Modify rules for when a user should be redirected.</li>
</ul>
How It Works:
<ul>
<li>Create and publish a page with your custom maintenance message.</li>
<li>Go to Settings > General and choose a Maintenance Mode Page or enter an External URL.</li>
<li>When enabled, visitors will be redirected to the selected page or URL. Logged-in administrators can still access the site.</li>
<li>The plugin does not affect the login page, REST API, or JSON endpoints.</li>
</ul>
This plugin is great for “coming soon” pages, staging site protection, design previews, or any situation where you need to hide the main site while keeping access for yourself.
<h3>Demo</h3>
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Simple Maintenance Redirect

Easily redirect visitors to a maintenance mode page or external URL while keeping access for logged-in administrators.

Fugu Design

One-click maintenance mode
This plugin adds a button to the admin bar for toggling the builtin maintenance mode.
Core maintenance mode
A .maintenance file is generated and copied to the WordPress installation folder when turning on the maintenance mode. 
A maintenance.php file is generated and added to the wp-content folder for custom HTML code.
Your custom maintenance page will also be active during the core, plugins and themes updates.
<h4>Special Features</h4>
<ul>
<li>
set which roles can switch the maintenance mode
</li>
<li>
set which roles can bypass the maintenance mode on the frontend
</li>
<li>
set the entire HTML code used for the maintenance page
</li>
<li>
preview the maintenance page before saving
</li>
<li>
enable the theme file support, so you can create in each your themes a maintenance.php file to customize the maintenance page
</li>
<li>
restore all default settings
</li>
<li>
restore default HTML code
</li>
<li>
create/delete the maintenance file in the active WP theme
</li>
</ul>
<h3>Translations</h3>
<ul>
<li>English – default, always included</li>
<li>French</li>
</ul>

Maintenance Switch

Customize easily and switch in one-click to (native) maintenance mode from your backend or frontend.

Simple Maintenance Redirect vs Maintenance Switch