Pages, renderings, placeholders, and content items

In Sitecore, a page consists of a page layout and renderings.

The page layout defines the overall structure of the page. A developer creates the page layout, which can contain placeholders where you can insert renderings.

A rendering defines a part of a page. It can contain layout information, for example, content fields and placeholders, and their positions on the page, as well as business logic or metadata for the page. Typically, you reuse renderings on multiple pages. If the rendering displays content, you can save the content on the page item or in a separate content item. You assign a content item to the rendering on the page, and you can reuse the content item on other pages.

When you add a rendering to a page, by default the rendering presents data that is saved on the page item. If you modify the content, the modifications are saved on the page item. Alternatively, you can assign a content item to the rendering. The content item may contain fields that the page item does not contain. Changes are saved to the content item, and the content can be shared between different pages.

A developer can configure a placeholder to only accept specific renderings. A developer can also configure the system so you can only select a compatible content item to assign to a rendering.