Mirte

If, for example, your clients want to be able to “turn off” their website for a while, so they can work on new 
content or features of their website, but you don’t want them rummaging through the WordPress Settings pages to do so, this plugin might be something for you.
This plugin creates a very simple little widget for your WP Dashboard, from which the website can turned to / out of maintenance mode.
Activating maintenance mode will display a maintenance mode page with explanatory text for your visitors. Logged in users will be able to view the website as they normally would.
The plugin will automatically create a <code>maintenance.php</code> file and add it to your <code>/wp-content/</code> directory. Customize this page to change the appearance and text of the maintenance mode page.
Known bugs 
* Right now, this plugin will not work on certain servers (like Antagonist.nl) because of a permissions issue.

Dashboard Maintenance Mode

Adds a nifty widget to your dashboard from which you can put your website in maintenance mode.

Beckin

Beckin Maintenance Mode is a lightweight, secure plugin that lets administrators safely put their WordPress site into maintenance mode without hurting SEO. It sends the proper 503 Service Unavailable header with an optional Retry-After value, shows a maintenance page to visitors while still allowing admin logins, and prevents caching to ensure your site reopens cleanly.
While maintenance mode is active, logged-in admins (and any other allowed roles) can continue working in the dashboard and browse the frontend normally. To preview the maintenance / coming soon page as a visitor, you can do any of the following:
<ul>
<li>Open your site in a different browser</li>
<li>Open an incognito or private window</li>
<li>Use a device where you are not logged in</li>
<li>Log out of the admin dashboard</li>
</ul>
The first 3 options easily let you preview the maintenance page without interrupting your own work. Everyone who is not logged in, or does not have permission to bypass maintenance mode, will see the maintenance page instead of your normal site.
FEATURES 
1. Smart 503 Response – Sends a proper HTTP 503 Service Unavailable header with optional Retry-After, which keeps your SEO safe. 
2. Admin Bypass – Admins can log in and keep working without being blocked, even while maintenance mode is active. 
3. Editor Bypass Mode – Optionally allow users who can edit posts (for example Editors and Authors) to keep working while visitors and subscribers see the maintenance page. 
4. Feed & API Safe – RSS feeds and REST API requests aren’t broken, so external tools and readers still function. 
5. Cache-Control Protection – Adds no-cache headers so the maintenance page isn’t cached by browsers or CDNs. 
6. Simple Settings Page – Clean and intuitive admin UI using core WordPress settings API, with sanitized input and escaped output everywhere. 
7. Admin Bar Badge – Shows a subtle “Maint. ON” badge when active for quick visibility. 
8. CLI Integration – Offers WP-CLI commands (wp beckin-mm enable|disable|status) for devs managing maintenance mode programmatically. 
9. Restricted Control – Only administrators (with the manage_options capability) can enable, disable, or change settings for maintenance mode. 
10. Lightweight & Secure – No bloat and zero dependencies 
11. Advanced Styling Controls – Customize the maintenance / coming soon page background colors, header and body text colors, and fully control the message box color and opacity, with a one-click Reset Style Settings button to restore defaults.
🌟 Like our plugin? Find it useful? Please consider sharing your experience by <a href="https://wordpress.org/support/plugin/beckin-maintenance-mode/reviews/" rel="ugc">leaving a review on WordPress.org</a>. Your feedback is instrumental to shaping our future growth!
<h3>CLI commands</h3>
<pre><code>wp beckin-mm enable
wp beckin-mm disable
wp beckin-mm status
</code></pre>

Beckin Maintenance Mode

A simple & lightweight, SEO-safe maintenance mode: 503 header + Retry-After, custom message, and admin bypass.

Dashboard Maintenance Mode vs Beckin Maintenance Mode