Experience Manager system diagram

Experience Manager consists of a client (editor) and an extension on the Content Manager server, and a Web service, Web site extension and database on the Content Delivery side.

System components installed on Content Manager:

Experience Manager client
The client is delivered as a GUI extension of the Content Manager of SDL Web, in the form of an Editor that implements Model-View-Controller software architecture. The client allows users to see a user-specific version of the staging Web site, showing each Web page with changes made by the current user (if any).
Content Manager Core, Content Manager Database
Any change that the user makes on a Web page, and then saves, leads to an update to the corresponding items in the Content Manager Database. The Content Manager Core also makes these changes available immediately to the user, through the Experience Manager extension; and eventually to all visitors of the staging Web site, through the normal publish mechanism.
Experience Manager Extension
The Experience Manager Extension to the Content Manager calls the Experience Manager Web service with any updates that the user made to items on the Web page, rendered into publishable form. This bypasses the publish cycle.

System components installed on Content Delivery:

Experience Manager Web service
The Experience Manager Web service receives updates from the Content Manager server and uses the Storage Layer to store the user-specific rendered content in a Content Data Store. Only the user who is making updates sees this content while editing; other visitors of the staging Web site see the latest content that is checked in on the Content Manager side.
Content Data Store (database configured for Experience Manager)
A Content Data Store is used for storage and retrieval of content within an editing session. The Content Data Store must be a relational database; a file system is not a supported storage medium for Experience Manager .
Content Deployer
The Content Deployer runs independently of the Experience Manager Web service to ensure normal deployment of content through publishing. Users of the user interface use the Content Deployer when they finish editing and make their changes available to all visitors of the staging Web site, or when they publish explicitly to the staging or live Web site.

Staging Presentation Server:

Staging Web site
The staging Web site is where users edit content in Experience Manager. The staging Web site always shows the latest published content.
Experience Manager Web site extension
The Experience Manager Web site extension ensures that when a user is editing the Web page, it shows the latest content as updated by the specific user who is logged in, and as checked in by other users, and stores the user's modifications in the Content Data Store (database configured for Experience Manager).