---
title: "Preview Servers"
description: "Set up and manage Preview Servers in Cloud CMS to review content changes instantly before going live. Discover server types and customization options. (Gitana 4.0)"
product: "Gitana"
version: "4.0"
url: "/documentation/gitana/4.0/engine/publishing/preview-servers"
---

# Preview Servers

Before your changes go to `Live` website i.e. on the **Production** mode, to discover problems and fix them right away you can set up the **Preview Servers** and review the content changes [instantly](/documentation/gitana/4.0/getting-started/editorial/instant-preview.md).

You can look at the default Preview Servers under Manage Project :

![previewserver.png](/documentation/gitana/4.0/engine/publishing/preview-servers/previewserver.png)

The default servers are `Authoring` and `Production` and are setup to a sample URL which can be modified with your website URL or some API or an Application.

To **add** your Custom Server, you can click on `Add Preview Server` and set-up the server as you intend to as follows:

![previewservers.png](/documentation/gitana/4.0/engine/publishing/preview-servers/previewservers.png)

You can choose your custom **Preview Server** as a **Preview Endpoint** for the [Lifecycle States](/documentation/gitana/4.0/engine/publishing/lifecycle-states.md).

To do that you can Go to **Lifecycle States**, under **Manage Project Publishing** Settings.

![custom-server.png](/documentation/gitana/4.0/engine/publishing/preview-servers/custom-server.png)

## Preview Server Types

Cloud CMS supports three different types of preview servers - `url`, `api` and `application`.

### URL

With this type of preview server, you simply provide a URL to an HTTP endpoint where the preview server lives. This URL may be a fixed value or it may use Handlebars to take advantage of one or more variables available to it. This allows the URL to adjust dynamically based on what is being viewed and who is viewing it.

The following model variables are available:

- `project` - the current Project
- `stack` - the current Project's Stack
- `user` - the current User
- `resource` - the current resource being viewed
- `datastore` - the DataStore where the current resource lives

If the item being viewed is a Node (which it typically is), then you'll additionally have the following:

- `repository` - the Repository where the current Node lives
- `branch` - the Branch where the current Node lives
- `node` - the current Node
- `document` - the current Node
- `paths` - a map of the file system paths for the current Node (or empty if not in a folder path)
- `rootPath` - the path of the Node relative to the Root Node of the branch

As such, you can set the URL to a fixed value, like:

```
http://preview.shopping.company.com
```

Or you can pass in values about what is being viewed, like this:

```
http://preview.shopping.company.com?node={{node.id}}&branch={{branch.id}}&path={{rootPath}}
```

Or use the values in the URI path itself, perhaps:

```
http://preview.shopping.company.com/preview/{{branch.id}}/{{node.id}}?user={{user.id}}
```

### API

When a node is previewed with an `api` preview server, the following URLs will be made available:

1.  A direct API URL to the JSON of the node, usually in the form:

```
GET /repositories/{repositoryId}/branches/{branchId}/nodes/{nodeId}
```

2.  Direct API download URLs for all the attachments. This is typically in the form:

```
GET /repositories/{repositoryId}/branches/{branchId}/nodes/{nodeId}/attachments/{attachmentId}
```

### Application

If you are taking advantage of Cloud CMS web rendition tracking (typically using the optional Cloud CMS Application Server's Dust processor), then Cloud CMS will keep track of pages on your website where a given node is used. As the Application Server renders pages that involve a node, a reverse map is essentially maintained so that you can quickly discover all pages where a node appears.

As such, if you set the type of the preview to `application`, you will be handed back a list of URLs where the node appears.