Optimizely Asynchronous Tag Setup Guide | Client-Side Tags

For options to implement Optimizely synchronously see this POST.

There are two methods of implementing the Optimizely Asynchronous tag. The content of your site and your testing requirements will determine which approach to use. We recommend that you try the two methods in the order they appear in this post.

NOTE: Both methods assume the utag.js file is coded asynchronously on the page.

Method 1 (RECOMMENDED): Bundle Optimizely Async Tag and load on all pages

We recommend this method because the tag will not block anything else from loading in the page.

Step 1: Enable the Bundling feature for Tags that will load on all pages.

In the admin menu, click Configure Publish Settings. The Publish Configuration dialog appears.
Turn ON the Bundle Tags Loading On All Pages toggle. This will bundle the Tag with utag.js, thus reducing the number of network calls made by the browser.

STEP 2: Add and set up the Optimizely Async Tag

This Tag is available in Tealium’s Tag Marketplace, which is home to a large selection of vendor tags. To learn more, see Tag Marketplace to learn how to add a Tag to your Tealium iQ profile.

/iq-tag-management/tags/manage/

Here are the steps to set it up:

Enter your Project ID. This is the number at the end of the script tag Optimizely sends you.
For example: <script src="//cdn.optimizely.com/js/123456789.js"></script>
Select Wait Flag = No from the Advanced Settings list.
Proceed to the Load Rules tab and check the default Load on All Pages rule.
Proceed to the Data Mappings tab and map the destinations you wish to send data to. To learn more, see Data Mappings to learn how to map a data source to a Tag destination.

If you plan to track E-Commerce data with the Async Tag, we recommend that you use the E-Commerce Extension to automatically map that data.

Destination Name	Destination Variable	Description	E-Commerce Extension Mapping (RECOMMENDED)
Project ID	`projectId`	Project identifier provided by Optimizely	N/A
Order ID	`orderId`	Unique identifier assigned to the order	`_corder` variable maps to this destination
Revenue in Cents	`revenue`	Subtotal amount (in cents) of the order	`_csubtotal` variable maps to this destination
Event Name	`eventName`	Name/Type of conversion event Default event is `purchase`	N/A

STEP 3: Save/Publish your profile.

IMPORTANT: For the Async Tag to fire as soon as possible, make sure the utag.js file is coded as high in the page as possible. We recommend placing the utag.js at the top of the HTML <body> tag. Tealium will load the Optimizely JavaScript file and take care of the rest.

Method 2: Run Optimizely as blocking Tag

Optimizely typically prefers to be synchronous on the page so it can run “sooner” and determine the test before other stuff (like your Analytics tool) runs. However, the only way to have Optimizely run soon enough and still be asynchronous is by serving its .js library from an alternate location. In doing so, the Optimizely Async Tag becomes a blocking Tag and any subsequent asynchronous scripts (for example, utag.10.js) will not load until the blocking Tag is complete.

Make sure to upgrade the utag.js version if you are not already using the latest. For more information, see utag.js Release Notes.

Repeat step #2 above to add and set up the Optimizely Async Tag.
Drop down the Advanced Settings and enter the location of the .js library in the Custom Script Source field.
Save/Publish your profile.

That’s it! A few simple differences, but this will dramatically change the way the Optimizely file is loaded and how other tags are loaded after Optimizely.