Optimizely Assistant Chrome extension

  • Updated
  • Optimizely Web Experimentation

The Optimizely Assistant Chrome extension for experimentation gives you insight into the nature of any Optimizely Experimentation activity occurring on your site. It also provides access to a suite of easy-to-use debugging tools. 


The Optimizely Assistant extension is a suite of utilities and tools with a comprehensive console log page. You can assess several important factors:

  • Whether Optimizely Experimentation is installed on the page.
  • What experiments and campaigns are currently active.
  • Which variations you are bucketed into.
  • Which Optimizely Experimentation pages are currently active.

You should use this tool in conjunction with other testing tools and techniques to test and vet your experiments in Optimizely Experimentation before you launch them.

Install the Optimizely Assistant

  1. Go to the Optimizely Assistant Chrome extension page.
  2. Click Add to Chrome to add the extension to your browser.
  3. Click the extension's Optimizely logo to enable the extension. 
  4. Follow the prompts to log in to your Optimizely Experimentation account and fetch the list of projects and snippets you have permission to view.
  5. Go to the site where you are using Optimizely Experimentation and open the Chrome JavaScript console to view messages:
    • On Windows and Linux, press Control-Shift-J.
    • On Mac, press Command-Option-J.
Log in to the Optimizely Experimentation Assistant extension to authorize using the extension for the projects related to your last-used account. If you believe the extension is warning you in error about not having the correct permissions, try the following:
  1. In a regular Chrome tab, using the user you will log in with the Optimizely Assistant, log in to Optimizely Experimentation.
  2. Switch accounts in Optimizely Experimentation to the account you want to use the extension with.
  3. Authorize the account in the Optimizely Experimentation Assistant.
    • If you have never logged in, click Open Login Pop-up.
    • If you have already logged in, click Settings and Log Out.
  4. Log in to Optimizely Experimentation again with the user from step 1.

This should authenticate you with the most recent account. If you continue to experience trouble, reference the Support section below.

One-click debugging tools


  • Add test cookie – Create or remove a test cookie so you can target an audience to it. This sets your experiment live in a way that ensures you are the only one seeing it.
  • Use Instant Snippet – Decrease the time between saving and testing your changes when building experiments and campaigns using the Amazon S3 version of the Optimizely snippet, which usually updates immediately and before Optimizely's distributed CDN. This only changes the version for your local Chrome environment, so your users continue to be served experiences from Optimizely's Content Delivery Network.
  • Swap snippet – Swapping a snippet is useful if an Optimizely Experimentation snippet is already on the page, but you need to test with a different snippet. For instance, you can use it to swap the production Optimizely Experimentation snippet into your site and test experiments in your own test environment. To swap it, you must have access to the account to which the snippet belongs.
  • Inject snippet – Useful if a webpage does not have an Optimizely Experimentation snippet and you want to add it. To swap it, you must have access to the account to which the snippet belongs.
  • Always use a non-cached snippet – Enable to immediately view changes you made in Optimizely Experimentation in your browser. 
    • It typically takes a few minutes for a change to propagate from your experiment in Optimizely Experimentation to Amazon’s servers and out to the CDN.
    • Custom snippets let you configure a longer TTL (time to live) for a snippet. The default setting is two minutes, but you can select a longer TTL to match your users' session duration. Longer TTLs mean end users have to fetch the Optimizely Experimentation snippet from the CDN less frequently, but Optimizely users have to wait longer to see changes to experiments.
  • Strip X-Frame-Options header – Removes any X-Frame-Options headers from your site, letting them load in the Optimizely Experimentation Editor.
  • Disable console logging – Prevent logs from printing in your console.
  • Disable Optimizely Experimentation – Determine which changes are influenced by Optimizely Experimentation and which are not.

Keyboard shortcuts

Save time by setting and using feature keyboard shortcuts. These can be set on the chrome://extensions/shortcuts page.