---
title: Use Tealium iQ with Optimizely snippet
slug: web-experimentation/docs/implement-the-snippet-with-tealium-iq
docTags: 
createdAt: 2026-07-23T11:40:25.851Z
---

:::hint{type="info"}
This is a third-party integration and is not an Optimizely subprocessor. See Optimizely's [Third-Party Add-Ons & Platform Integration Terms](https://www.optimizely.com/legal/third-party-add-ons-platform-integration-terms/).
:::

This topic describes how to implement the Optimizely snippet if you use Tealium iQ, synchronously and asynchronously.

When you configure Optimizely Web Experimentation for the first time, you implement the [Optimizely snippet](docId\:Eynqg8Z-62r76dvDho6dx). There are two ways to implement Optimizely within Tealium: [synchronously and asynchronously](docId\:Q_zBOGZuwMtPCS1rnkUJK). This article describes both approaches.

:::hint{type="info"}
**📘 Note**
In general, Optimizely recommends loading the snippet outside of a tag manager.
:::

## Synchronous loading

To load Optimizely synchronously, the Tealium snippet must also be loaded synchronously. Edit your template in Tealium iQ.

1. Click the drop-down list near your name and select **Manage Templates**.
2. Select **uTag Sync (Profile) UID\:sync**.
3. Paste the following code in the **Template Config** code sandbox under the existing text:

```javascript
document.write('<script type="text/javascript" src="//cdn.optimizely.com/js/12345678.js"></script>');
```

:::hint{type="info"}
**📘 Note**
Use your Optimizely snippet code in this script. Replace ‘12345678’ above with your actual project ID.
:::

After you enter the Optimizely code, you can save, publish, and integrate Optimizely with your analytics platform. The only difference between using Tealium and adding tags directly to your page is that you place the analytics tracking calls in the appropriate tags or extensions within Tealium.

## Asynchronous loading

With the asynchronous method, you run Optimizely asynchronously while blocking other tags and elements from loading until Optimizely is finished loading. You need to block the other tags because if Optimizely still loads after items like analytics tags and page elements execute, your other analytics integrations could break.

You may also see a "flicker" or "flash" effect when the original page shows briefly before the variation loads.

1. Confirm that you already configured your analytics integrations in Optimizely. The only difference from adding these tags directly to your page is that you place the analytics tracking calls in the appropriate tags or extensions within Tealium.
2. Confirm that you updated Tealium to the latest `utag.js` template.
3. Within Tealium, select the **Tags** tab and click **Add Tag**.
4. Search for **Optimizely (Async)** and click **Add**.
5. Go to **Vendor Configuration > Tag Configuration** and click **Extract from Code**.
6. Paste in your Optimizely snippet and click **Extract**.
7. Click **Advanced Settings** and set **Wait Flag** to **No**.
8. In the **Custom Script Source** field, add your Optimizely snippet, starting with the two slashes, such as `//cdn.optimizely.com/js/12345678.js`.
9. Add a note to indicate that you are using Optimizely as a blocking tag.
10. Confirm that Optimizely is first in the list of tags in Tealium.