Core Roles and non-core Roles

Content Delivery functionality consists of a number of Roles. A Role is (the Content Delivery side of) a product feature. We distinguish between core Roles, which are always needed to get the product up and running, and non-core Roles, which you may or may not install based on business needs.

Core Server Roles

The core Content Delivery Roles are:
RoleDescription
Discovery ServiceExposes the Discovery Endpoint, through which all Content Delivery services are made available.
Content ServiceExposes a number of core Content Delivery APIs for the presentation environment to interact with.
Content DeployerDeploys content published from Content Manager.
SearchEnables search functionality on Content Delivery-based websites.
User Generated Content (UGC)Enables commenting and rating on the published website. Note that you cannot use the same UGC instance for both SDL Tridion Sites and SDL Tridion Docs.

Nonessential Server Roles

The nonessential Server Roles are:
Server RoleDescription
Context EngineEnables the discovery of, and ability to respond to, contextual information about the visitors of your website, and about the devices they use.
Contextual Image DeliveryEnables request-time image transformation on the published website.
Context Expression ExtensionMakes campaign management and analysis data available for use on your SDL Tridion Docs-based website. To use the Context Expression Extension, you must have the add-on product SDL DXA set up, and specifically the Context Expression Module of that product.