A plug-in is custom business logic (code) that you can integrate with Dynamics 365 (online) Customer Engagement to modify or augment the standard behavior of the platform. Another way to think about plug-ins is that they are handlers for events fired by Dynamics 365. You can subscribe, or register, a plug-in to a known set of events to have your code run when the event occurs.
The feedback system for this content will be changing soon. Old comments will not be carried over. If content within a comment thread is important to you, please save a copy. For more information on the upcoming change, we invite you to read our blog post.