PeoplesGeek

Monitoring services like www.siteuptime.com or www.montastic.com require a page on your website to monitor.
This plugin provides a virtual target for your monitoring services that does not invoke other plugins (specifically avoiding the Google analytics plugins so that your statistics are not skewed by monitoring calls) 
The two targets provided for the monitoring service are:
<ul>
<li>monitor.htm – via .htaccess and does not use WordPress (but does use PHP)</li>
<li>monitorWP.htm – via WP and so tests the Database etc is working</li>
</ul>

PG Monitor

A virtual target file to be read by monitoring services instead of using a static HTML page.

pianoweb

SentWatch monitors WordPress email delivery reliability with instant notifications when problems occur.
The plugin sends periodic “heartbeats” to our monitoring service. If these signals stop arriving, it means your site has stopped sending emails (SMTP issues, plugin conflicts, server problems), and we notify you immediately.
Key Features:
<ul>
<li>Hybrid Heartbeat System – Uses HTTP API with email fallback for maximum reliability</li>
<li>Automatic Time Sync – Plugin synchronizes with server time to prevent false alarms</li>
<li>Instant Notifications – Get alerts immediately when email delivery fails</li>
<li>Zero Configuration – Just enter your API key and you’re done</li>
<li>Lightweight – No performance impact on your site (runs in background)</li>
<li>Smart Scheduling – Heartbeats are automatically aligned with server expectations</li>
</ul>
How It Works:
<ol>
<li>Plugin sends a “heartbeat” signal at regular intervals</li>
<li>Our server tracks when heartbeats arrive</li>
<li>If a heartbeat is missed, we verify your site is reachable</li>
<li>If the issue persists, you receive an instant email notification</li>
</ol>
Subscription Plans:
<ul>
<li>Free – 1 site, 24-hour monitoring interval</li>
<li>Silver – 10 sites, 12-hour interval</li>
<li>Gold – 50 sites, 6-hour interval</li>
<li>Platinum – 200 sites, 3-hour interval</li>
</ul>
Note: This plugin requires a free account on <a href="https://panel.sentwatch.com/register.php" rel="nofollow ugc">SentWatch</a>.
<h3>External Services</h3>
This plugin connects to the SentWatch monitoring service to provide email delivery monitoring functionality.
Service Provider: SentWatch (operated by PianoWeb) 
Service URL: https://panel.sentwatch.com
What data is transmitted:
<ol>
<li>
During initial setup – When you connect the plugin with your API key:
<ul>
<li>Site URL</li>
<li>Site name</li>
<li>WordPress version</li>
<li>PHP version</li>
<li>Plugin version</li>
</ul>
</li>
<li>
During periodic heartbeats – Sent via email at intervals determined by your plan (every 3-24 hours):
<ul>
<li>Timestamp</li>
<li>Site URL</li>
<li>Plugin version</li>
</ul>
</li>
<li>
During status checks – When you view the plugin settings page or when the plugin syncs configuration:
<ul>
<li>Site UUID (unique identifier)</li>
<li>API Key (for authentication)</li>
</ul>
</li>
</ol>
When data is sent: 
– On initial plugin activation and setup 
– Periodically via scheduled email heartbeats (frequency depends on your subscription plan) 
– When you manually test email delivery 
– When the plugin checks for configuration updates (daily)
Why this data is sent: 
This data is necessary for the monitoring service to track whether your WordPress site is successfully sending emails. If heartbeat emails stop arriving, the service alerts you that your site’s email functionality may be broken.
Legal: 
– Terms of Service: https://panel.sentwatch.com/terms.php 
– Privacy Policy: https://panel.sentwatch.com/privacy.php
By using this plugin, you acknowledge that your site will communicate with the SentWatch service as described above.

SentWatch – Email Uptime Monitoring

Monitor WordPress email delivery with instant notifications when problems occur.

PG Monitor vs SentWatch – Email Uptime Monitoring