Plugins are used to achieve custom functionalities before or after core application execution. To developed plugin Microsoft Software Development Kit is required. You can download CRM SDK from Microsoft Site. You can also find some sample code along with SDK which helps you develop plugin.
Before develop plugins in CRM is also required to understand exception pipe line and stage to trigger custom code. In Image you can see CRM execution pipe line flow-
Plugin deployment in Microsoft Dynamics CRM is either Sandbox (Partial Trust) and outside of Sandbox full trust. If plugin is deployed in isolation mode, it will run with partial trust. The level of isolation allows HTTP and HTTPS web resources for external requests using Dynamics CRM web service.
To deploy a plugin without isolation mode, you need to deploy it using deployment manager and deploy administration is required for it.
There are two modes
There are three stages for plugin code execution event–