Katsushi Kawamori

<h4>Messenger</h4>
<ul>
<li>All logged in users post and display messages.</li>
<li>The default number of items displayed is 100; if more than 100 items are displayed, they are erased in order of oldest to newest. This can be changed with the following filter.</li>
<li>The default user permission is “read”, so all users can use it. This can be changed with the following filter.</li>
<li>The display is updated at 1-second intervals. This can be changed with the following filter.</li>
</ul>
<h4>Notifies</h4>
<ul>
<li>Notify unread messages in a modal window at 60 second intervals. This can be changed with the following filter.</li>
</ul>
<h4>Title</h4>
<ul>
<li>The default title is “All Users Messenger”. This can be changed with the following filter.</li>
</ul>
<h4>How it works</h4>
<span class="embed-youtube" style="text-align:center; display: block;"><iframe class="youtube-player" width="640" height="360" src="https://www.youtube.com/embed/htygEVp6594?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation"></iframe></span>
<h4>Filter hooks</h4>
<ul>
<li>The number of messages displayed can be customized. The default is 100 messages.</li>
</ul>
<pre><code>/** ==================================================
 * Number of messages displayed filter. Default 100.
 *
 */
add_filter( 'all_users_messenger_messages_max', function(){ return 200; }, 10, 1 );
</code></pre>
<ul>
<li>Usage permission filter. Default is read.</li>
</ul>
<pre><code>/** ==================================================
 * Capability filter for use. Deafult read.
 *
 */
add_filter( 'all_users_messenger_capability', function(){ return 'edit_post'; }, 10, 1 );
</code></pre>
<ul>
<li>The interval between message displays can be customized. The default is 1 second.</li>
</ul>
<pre><code>/** ==================================================
 * Message display interval filter. Default 1 sec.
 *
 */
add_filter( 'all_users_messenger_interval', function(){ return 2; }, 10, 1 );
</code></pre>
<ul>
<li>The unread check interval for displaying unread messages in the modal window in the administration screen. The default is 60 seconds.</li>
</ul>
<pre><code>/** ==================================================
 * Notification unread messages interval seconds filter for modal windows. Default 60 sec.
 *
 */
add_filter( 'all_users_messenger_notify_interval', function(){ return 120; }, 10, 1 );
</code></pre>
<ul>
<li>This is the filter for the menu title. The default is “All Users Messenger”.</li>
</ul>
<pre><code>/** ==================================================
 * Menu tite filter. Default All Users Messenger.
 *
 */
add_filter( 'all_users_messenger_page_title', function(){ return 'Chat'; }, 10, 1 );
add_filter( 'all_users_messenger_menu_title', function(){ return 'Chat'; }, 10, 1 );
</code></pre>
<ul>
<li>This is filter for display modal window. The default is True.</li>
</ul>
<pre><code>/** ==================================================
 * Display to the modal window filter. Default True.
 *
 */
add_filter( 'all_users_messenger_modal_view', function(){ return false; }, 10, 1 );
</code></pre>
<h4>Action hooks</h4>
<ul>
<li>This deletes all messages.</li>
</ul>
<pre><code>/** ==================================================
 * Delete all messages.
 *
 */
do_action( 'all_users_messenger_clear_messages' );
</code></pre>


All Users Messenger

Messages can be sent, received, and shared among all logged-in users.

Facebook

<p>Communicate with customers on your website with Messenger-powered chat. Chat Plugin is a chat widget maintained by the Meta Business that enables live chat on your website.</p>
<p>Whether they’re on their computer or their phone, website visitors will be able to message you anytime by clicking on a small Messenger chat bubble in the lower right corner of your site.</p>
<p>Key features:</p>
<ul>
<li>Website visitors can message you while browsing your site.</li>
<li>Set up auto-replies and answers to common questions to serve customers when you’re not available.</li>
<li>Continue the conversation with customers on Messenger even after they leave your website.</li>
<li>Visitors without a Facebook Messenger account can ask you questions anonymously in Guest mode.</li>
<li><a href="https://www.facebook.com/business/messenger/get-started" rel="nofollow ugc">Messenger</a>’s familiar interface builds trust.</li>
<li>No need to switch between apps to answer questions you get on the website.</li>
</ul>


Facebook Chat Plugin – Live Chat Plugin for WordPress

The Facebook Chat Plugin makes it easy for your website visitors to chat with you and ask you questions, even if they don't have Messenger.

All Users Messenger vs Facebook Chat Plugin – Live Chat Plugin for WordPress