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Monthly unique visitors (MUVs)

  • Updated
This topic describes how to:
  • Avoid monthly unique visitor overages or experiment interruptions
  • Adjust your monthly unique visitor budget

A monthly unique visitor (MUV) is an individual user who accesses your site within 30-day window. Optimizely tracks unique visitors with a cookie (optimizelyEndUserID) that lasts for 10 years or until users clear their browser cookies. Optimizely bills your account based on the number of MUVs who enter an experiment on your site.

Please note that billing for MUVs is slightly different from the unique visitors counted by Optimizely's Results page. Imagine that a single individual visits your website four times in four months: once in each of February, March, April, and May. For billing purposes, Optimizely counts these visits as four total MUVs. However, the Optimizely Results page is calculated based simply on unique visitors. This individual is counted only once in your experiment results.

Optimizely Web Experimentation and Optimizely Full Stack are billed by MUVs, but MUVs used with Optimizely Web Personalization are unlimited, site-wide.

If you are using Experimentation-in-Personalization and testing multiple variations for a single audience in a Personalization campaign, Optimizely counts the visitors you bucket into these variations as Experimentation MUVs and bills you accordingly.

Standard, Professional, and Premium packages

If you have a Standard, Professional, or Enterprise package in Optimizely or Full Stack, exceeding your MUV limit can result in overage charges for your account. Overage charges depend on your contract.

To avoid overage charges, pause experiments when the MUV count approaches your limit. Use email alerts to receive an notification when you are approaching your MUV budget.

Optimizely does not automatically pause experiments for Enterprise, Standard, Professional, or Premium plans.

I am using more MUVs than I expected

In some cases, you may see extra visitors counted and listed as MUVs on your bill. The Optimizely snippet, which pauses your experiment when you reach your budget, is usually updated within a few minutes of pausing your experiment. However, there may occasionally be a delay—and you will see extra visitors counted.

Optimizely protects you against being over-charged for MUVs in two ways:

  • Optimizely does not bill you for visitors who were not counted due to delays at the time when your bill is sent out.

  • To ensure an accurate MUV count, Optimizely removes duplicate unique visitors. For example, imagine that you run three experiments and run through 6 million visitors. But some visitors may see more than one experiment—so your traffic is actually closer to 2 million unique visitors. Optimizely removes duplicate unique visitors so you are correctly charged for your MUVs.

Have more questions about your MUVs? Please contact your Customer Success Manager or file a support ticket.