Jan Štětina

This plugin provides a simple API for storing miscellaneous log entries and their overview in admin area (or network 
admin area, if activated on a multisite).
Developed for private use (heavily used by my other plugins), but has perspective for more extensive usage. I can’t guarantee any support in the future nor further development, but it is to be expected. Kindly inform me about bugs, if you find any, or propose new features: <a href="mailto:zaantar@zaantar.eu?subject=[wordpress-logging-service]" rel="nofollow ugc">zaantar@zaantar.eu</a>.
See Usage and FAQ for more information.
<h3>API</h3>
Definitions:
<pre><code>WLS
</code></pre>
<ul>
<li>
should be checked before using any wls function
WLS_VERSION
</li>
<li>
should(!) contain current WLS version string
</li>
<li>
severity levels:
<pre><code>WLS_NOCATEGORY = 0

WLS_INFO = 1

WLS_NOTICE = 2

WLS_WARNING = 3

WLS_ERROR = 4

WLS_FATALERROR = 5
</code></pre>
</li>
</ul>
Functions:
<pre><code>wls_is_registered( $category_name );
</code></pre>
<ul>
<li>
returns <code>true</code>, if <code>$category_name</code> is registered
wls_register( $category_name, $description );
</li>
<li>
registers <code>$category_name</code> as a log category.
</li>
<li>
<code>$description</code> will be shown in admin area
wls_clear( $category_name );
</li>
<li>
deletes all log entries of category $category_name
wls_unregister( $category_name );
</li>
<li>
same as wls_clear & removes category $category_name from the list
wls_log( $category_name, $text, $user_id, $date, $blog_id, $severity = 0 );
</li>
<li>
inserts a new log entry into specified category
</li>
<li><code>$date</code> must be formated according to ISO 8601</li>
<li>
<code>$severity</code> should be one of defined severity levels (see above)
wls_simple_log( $log_name, $text, $severity = 0 );
</li>
<li>
equivalent to <code>wls_log( $category_name, $text, get_current_user_id(), date( 'c' ), get_current_blog_id(), $severity);</code>
</li>
</ul>

WordPress Logging Service

Provides a simple API for storing miscellaneous log entries and their overview in admin area.

Kunal

Custom 404 Pro replaces WordPress’s default 404 behaviour with a proper redirect. Instead of leaving visitors on a dead-end error page, you can send them to any page on your site or an external URL — with the HTTP status code of your choice.
<h4>Redirect Modes</h4>
<ul>
<li>WordPress Page — pick any published page from a dropdown; the plugin redirects to it automatically.</li>
<li>Custom URL — enter any absolute URL to redirect 404s off-site or to a specific path.</li>
<li>HTTP Status Code — choose 301, 302, 307, or 308 to match your SEO or caching requirements.</li>
</ul>
<h4>404 Logging</h4>
When logging is enabled, the plugin records every 404 hit to a database table so you can see exactly what is broken:
<ul>
<li>Request path</li>
<li>Visitor IP address (can be disabled for privacy/GDPR compliance)</li>
<li>Referrer URL</li>
<li>User agent</li>
<li>Timestamp</li>
</ul>
Logs are searchable and can be deleted individually, in bulk, or all at once. They can also be exported as a CSV file. A configurable retention policy lets you automatically cap the table by row count, by age, or both — with a daily background cleanup and an on-demand Prune Now button.
<h4>Email Notifications</h4>
Optionally receive an admin email each time a 404 is logged. Designed for low-traffic monitoring — if you expect high 404 volume, keep this off to avoid inbox flooding.
<h4>Multisite Support</h4>
Works correctly on WordPress Multisite installations — activation creates the logs table for each site in the network.
<h4>Multilingual Support</h4>
Compatible with Polylang and WPML. The redirect page is resolved to the correct language variant for the current visitor automatically.

Custom 404 Pro

Take control of every 404 on your site — redirect visitors to a custom page or URL, log what broke, and get notified when it matters.

WordPress Logging Service vs Custom 404 Pro