Learn More: Implementing the snippet


To start running A/B tests on your site, you'll need to add a small snippet of code to the <head> tag of your site's code. This snippet contains your unique Project ID, and it allows the experiments you create in Optimizely to execute on your site.

After this, you won't have to update the snippet for future experiments. The snippet will automatically update to run any tests you create in the Optimizely editor. You don’t have to change a thing.

To start testing, you'll just need to add the Optimizely snippet to all pages where you'd like to:

  • Run an experiment or
  • Track experiment goals

Once you have added the snippet to your page, you will not need to update it again. We recommend adding the Optimizely snippet to all pages on your site.

When you're ready, close this Lesson and open the video that follows, where we'll guide you through a step-by-step process to help you install the snippet.


Please do not modify the snippet. Copy and paste it onto your site exactly as you see it within Optimizely. Otherwise, Optimizely may not run correctly on your site.