You deploy a plug-in package to the vSphere Web Client by registering the package as an extension on vCenter Server. When you register your plug-in as an extension on vCenter Server, your plug-in becomes available to any vSphere Web Client that connects to your vSphere environment.

You must register your plug-in on every vCenter Server where you need to use it. When a vSphere Web Client connects to a vCenter Server where your plug-in is not registered, the plug-in is not visible to the client.

When a vSphere Web Client establishes a user session to a vCenter Server instance, the vSphere Web Client application server queries vCenter Server for a list of all available plug-in packages that are registered as vCenter Server extensions. Plug-in packages that are not present on the vSphere Web Client application server are downloaded and installed.

The vSphere Web Client application server can run only one version of each plug-in package. If a plug-in package is present on the application server, but has an older version number than the registered vCenter Server extension, the registered vCenter Server extension replaces the older plug-in package.