In-website preview for PHP

When working in the writing room, authors can preview their new content on their website without having to publish the document.

1. Include the Prismic Toolbar javascript file

Next you will need to include the Prismic toolbar scripts on every page of your website. This means including it on your 404 page!

You can find this script in your repository 'Settings' section, under the 'Previews' tab.

Settings > Previews > Script

This toolbar will add a preview cookie when a user hits the preview button. 

This cookie contains the preview ref needed to call the API and receive the proper content.

Note for Sharable Previews & unpublished previews

To guarantee that Sharable Previews and unpublished document previews work properly you must ensure that these scripts are included on every page of your website, including your 404/Page Not Found page. Otherwise these previews might not work.

2. Setup a preview environment

In your repository, head to the Settings / Previews. Add a site name and the domain for your website where you wish to preview your content. You can also add an optional Link Resolver route which you will learn more about in the next section.

The interface to add a new Preview in Prismic

Note that you can also enter localhost domains such as:


If you are using our official Prismic PHP development kit (php-kit), then that is all you need to do to gain the basic functionality of the Preview feature! If you are not using this kit to make your queries, then refer to the "Use the correct ref" section below.

With the basic functionality of the Preview feature, when you click on the preview button, you will be taken to the homepage of your preview domain. From here you can navigate to the page you are trying to preview.

Next we will show you how to add a Link Resolver endpoint so that you will be taken directly to the page you are trying to preview.

In order to be taken directly to the page you are previewing instead of the homepage, you need to add a Link Resolver endpoint. A typical example of this would be:


In your preview settings add this endpoint to the optional Link Resolver field.

Where to add a Link Resolver endpoint to your preview in Prismic.

Using an official Prismic starter project?

If you are using one of our official Prismic starter projects, then you should already have all the code in place you need for In-website previews. That's as much as you need to do!

If you're not using an official Prismic project, then follow the rest of the steps below.

Now you need to add the Link Resolver endpoint in your website application. When requested this endpoint must:

  • Retrieve the preview token from the token parameter in the query string
  • Call the Prismic development kit with this token and the Link Resolver will retrieve the correct URL for the document being previewed
  • Redirect to the given URL

The Preview Token

Note that the preview token will be a URL. You DO NOT need to follow this url. All you need to do is pass this token into the previewSession method as shown below

$token = isset($_GET['token']) ? $_GET['token'] : null;
if (!isset($token)) {
    header('HTTP/1.1 400 Bad Request', true, 400);
    exit('Bad Request');
$url = $api->previewSession($token, $linkResolver, '/');
header('Location: ' . $url);

The example above uses a Link Resolver function stored in the variable $linkResolver to determine the end url to redirect to. To learn more about how to set this up, check out our Link Resolving page.

4. Use the correct reference

Are you using our php-kit?

This last step is only required if you are not using the php-kit to retrieve your API object.

If you are using the Api::get method to retrieve your API object, then the correct reference will automatically be used and this last step is not necessary. If you are not using this method, then do the following:

When you preview your website, a preview cookie is generated that contains the preview token. This token can be used as a valid ref to make Prismic API queries. For any query you make on your website, make sure to check for the Preview cookie and use this preview ref in the query options if the preview cookie exists.

Here is how to retrieve the correct ref:

// Example ref selection for PHP - This is already done with the PHP kit
function getPreviewRef() {
    $cookieNames = [
        str_replace(['.',' '], '_', Api::PREVIEW_COOKIE),
    foreach ($cookieNames as $cookieName) {
        if (isset($_COOKIE[$cookieName])) {
            return $_COOKIE[$cookieName];
    return null;

$previewRef = getPreviewRef();
$ref = $previewRef ? $previewRef : $api->master()->getRef();

Then here is an example that shows how to use this ref in your query:

$response = $api->query(
    Predicates::at('document.type', 'blog-post'),
    [ 'ref' => $ref ]
// $response contains the response object

And with that you should have everything in place that you need to begin previewing your content!

5. Troubleshooting

Mistakes happen. So sometimes you might to do a little troubleshooting to figure out where exactly the problem is from, luckily we've created an article for just that.