Akeda Bagus

This plugin is an extension to <a href="https://wordpress.org/plugins/slack" rel="ugc">Slack plugin</a> that allows you to send notifications to Slack channels whenever payment in WooCommerce is marked as complete.
The new event will be shown on integration setting with text When a payment in WooCommerce is marked as complete. If checked then notification will be delivered once payment is marked as complete.
You can alter the message with <code>slack_woocommerce_order_status_completed_message</code> filter. The filter receives following parameters (ordered by position):
<ul>
<li><code>$message</code> — Default string of message to be delivered</li>
<li><code>$order</code> — Order object</li>
</ul>
Development of this plugin is done on <a href="https://github.com/gedex/wp-slack-woocommerce" rel="nofollow ugc">GitHub</a>. Pull requests are always welcome.

Slack WooCommerce

Send notifications to Slack channels whenever payment in WooCommerce is marked as complete.

Michele Albert

Ultimate Slack Notifications

Notify your team members with each WordPress site activities by sending customized messages into Slack channels

Slack WooCommerce vs Ultimate Slack Notifications