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:
| Role | Description |
|---|
| Discovery Service | Exposes the Discovery Endpoint, through which all Content Delivery services are made available. |
| Content Service | Exposes a number of core Content Delivery APIs for the presentation environment to interact with. |
| Content Deployer | Deploys content published from Content Manager. |
| Search | Enables 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 Role | Description |
|---|
| Context Engine | Enables the discovery of, and ability to respond to, contextual information about the visitors of your website, and about the devices they use. |
| Contextual Image Delivery | Enables request-time image transformation on the published website. |
| Context Expression Extension | Makes 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. |