External Notification is a plugin that allows users to send a notification to Slack. Also it has useful hooks for developers. Default function When WordPress sends a notification email for site administrators, this plugin sends the message to slack instead of an email. This feature can be disabled from the administration screen. How to use the plugin as a notification API There are 2 ways to use the plugin as the API. 1. Call the ready-to-use external_notification2slack function external_notification2slack($message, $user_id, $payload) 2. If another plugin will use this to post slack, it is best to use this option instead of calling external_notification2slack function to avoid Fatal Error in case this plugin is deactivated.\ do_action( 'external_notification2slack', $message, $user_id, $payload ); For developers ‘webhook_url’ acquisition priority constant ‘EXNO_SLACK_WEBHOOK_URL’ in wp-config.php ‘webhook_url’ entry in External Notification option page logging error messages if you install & activete our another plugin ‘App Log’, outputs an error message to the log file.