relevant products:
  • Optimizely X Web Experimentation
  • Optimizely X Web Personalization
  • Optimizely X Full Stack
  • Optimizely X Mobile
  • Optimizely Classic
  • Optimizely Classic Mobile

This article will help you:
  • 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.

All of Optimizely's experimentation products are billed by MUVs:

  • Optimizely Classic

  • Optimizely X Web Experimentation

  • Optimizely Classic Mobile

  • Optimizely X Mobile 

  • Optimizely X Full Stack

Optimizely X Web Personalization is the exception; MUVs used with Personalization are unlimited, site-wide.

If you're 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.

Enterprise Standard, Professional, and Premium plans

If you have an Enterprise Standard, Professional, or Premium plan, 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’re approaching your MUV budget: in Optimizely Classic and Optimizely X.

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

Pay As You Go plan

On a Pay As You Go plan, you'll set a budget for the MUVs that your account uses in a 30-day billing period. The rate is $49 per 1000 visitors.

If you reach your pre-set limit, Optimizely automatically pauses the experiment so you won't be charged for overages. To resume your experiment, raise your MUV budget.

You can also prevent service interruptions by setting up an email alert to ensure that you know when you're approaching your MUV budget. Adjust your email alert preferences: Optimizely Classic or Optimizely X.

I'm using more MUVs than I expected

If you’re migrating from Optimizely Classic to Optimizely X (or still using both), please be aware that your Classic traffic counts towards your MUVs.

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'll see extra visitors counted.

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

  • Enterprise Standard, Professional, or Premium plans: Optimizely adds 1000 extra MUVs to the monthly limit.

  • Pay-as-you-go plans: Optimizely provides a $5 credit each month.

  • Optimizely doesn’t bill you for visitors who weren't 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're correctly charged for your MUVs.

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