• Optimizely X Web Experimentation
  • Optimizely Performance Edge
This article will help you:
  • Change the percentage of total traffic that's eligible to enter your experiment
  • Change what percentage of your experiment traffic sees each variation
  • Stop a variation

By default, Optimizely allocates 100% of visitors to experiments and distributes traffic equally among variations. You can reallocate and redistribute traffic (described below), but we don't recommend this for running experiments. Here's how to send all traffic to a winning variation in an experiment. 

Optimizely Performance Edge is a lightweight experimentation product that delivers significantly faster performance than previous versions of Optimizely. It does this by relying on a streamlined "microsnippet" which limits the range of available features.

Optimizely Performance Edge and Optimizely X Web handle traffic allocation the same way, so all information contained in this article applies to experiments created with either version of Optimizely.

Read on to learn how to control traffic allocation and distribution in Optimizely X.

Re-allocate and re-distribute traffic

To change traffic allocation and distribution for variations in Optimizely X:


  1. From the Experiments dashboard, navigate to your experiment.

  2. Under Manage Experiment, select Traffic Allocation.

    You can also change your traffic allocation and distribution directly from the Results page. Click Edit Experiment > Traffic Allocation.

  3. In the Traffic Allocation dialog, under Experiment Traffic Allocation, change the percentage of eligible visitors who enter your experiment. If you choose 50%, half of the visitors who land on your page and meet your audience conditions will enter the experiment and be tracked in results.

    Under Variation Traffic Distribution, you can adjust the percentage of traffic that will be bucketed into a particular variation. For example, if you have four variations and the traffic is distributed equally, each new visitor has a 25% chance of being placed into each variation.

    Changes to traffic distribution will only affect new visitors. Existing visitors (whether or not they were bucketed in a variation) will keep seeing the same variation, even after you change traffic distribution. Visitors who are excluded from the experiment will always be excluded.

    Changes to traffic allocation, however, can potentially affect all visitors. If, for example, you were to set traffic allocation to zero, returning visitors who have previously been bucketed into an experiment will not see the variation to which they'd been assigned, and will instead get the same experience as everyone else.

  4. Click Save.

If you are changing the traffic allocation from a previously published traffic allocation, Optimizely will add a yellow "changed" label indicating that this traffic allocation has not been published yet.


You will need to click on "Publish Experiment" for the new traffic allocation to take into effect.

Changing traffic allocation may affect your experiment results and make it difficult to interpret them correctly.

Stop a variation