Improve email campaign performance with Audience Optimization

You will learn

• What Audience Optimization is and how it differs from Suppressions.
• How to set up a campaign with Audience Optimization, in any supported channel.
• How to view and interpret Audience Optimization performance reports.
• Eligibility, supported channels, and current limitations.

What is Audience Optimization?

Audience Optimization helps improve campaign performance by using a predictive model to identify recipients who are unlikely to engage or convert, or likely to unsubscribe, and removing them from a send before it goes out.

Who can use Audience Optimization

Audience Optimization is available with the following scope:

• Plans: Available to customers on the Marketing Analytics or Advanced Klaviyo Data Platform (Advanced KDP) packages.
• Channels: Email, SMS, RCS, WhatsApp, and Push, including omnichannel campaigns.

How to use Audience Optimization

1. Create a campaign

• Go to Campaigns and create a new campaign in any supported channel (email, SMS, RCS, WhatsApp, Push) or an omnichannel campaign.
• Choose your target audience (lists and/or segments) in the Audience step.

2. Find the Audience Optimization toggle

In the Audience step of a campaign, look for the Audience Optimization option once an audience has been selected.

Note: The Audience Optimization toggle does not appear if your account is currently in Reputation Repair.

3. Turn on Audience Optimization

• Turn on the Audience optimization toggle.
• For omnichannel campaigns: turning on Audience Optimization at the omnichannel level applies it to all enabled channels in that campaign by default.

4. Review and schedule your campaign

• Continue to the review & schedule step.
• Schedule or send your campaign.

At the time Klaviyo determines the recipients for the campaign, the Audience Optimization model runs against the final set of eligible recipients and removes the highest-risk profiles before the messages are delivered.

How Audience Optimization works

Audience Optimization uses a predictive model to estimate each recipient’s likelihood of engaging, converting, or unsubscribing. The model considers engagement events and rates, onsite activity, conversion signals, and several company-level features such as sends per profile and total number of profiles to make these predictions.

Profiles predicted to be unlikely to engage or convert, or likely to unsubscribe, are removed; all other eligible profiles remain in the send group.

To avoid permanently sidelining recipients, Audience Optimization includes a cool‐off safeguard:

• If a profile has not received any messages in the past 30 days, their risk score is temporarily treated as very low, allowing them to receive messages again after a cooling period.
• This creates opportunities to re‐engage previously removed profiles with more relevant content and lower frequency.

Audience Optimization Analytics

Audience Optimization includes analytics to help you understand who was excluded from a campaign and the overall impact of optimization on your performance.

View analytics for a campaign

Within each campaign, the Audience Optimization card provides a quick summary of how many recipients were excluded from each campaign send.

• Profiles removed: This number shows how many recipients were excluded by Audience Optimization for that specific campaign. These are profiles predicted to be unlikely to engage or convert, or likely to unsubscribe.

You can click on the Profiles removed number to view the full list of excluded recipients in the Recipient activity → Optimized tab.

To locate Audience Optimization analytics:

1. Navigate to a specific campaign.
2. On the campaign’s overview page, find the Audience Optimization card below the overall campaign metrics.

View excluded recipients for a campaign

You can see which profiles were removed from a specific campaign due to Audience Optimization.

To access this list:

1. Navigate to a campaign’s Recipient activity tab.
2. Select the Optimized subtab.

This view shows the profiles that were removed by Audience Optimization for that send.

For quicker access, you can also:

• Go to the Campaigns overview page
• Locate the Audience Optimization card
• Click the number of profiles removed to open the full list of profiles removed.

Understand aggregate impact

To help you understand long-term impact, Klaviyo surfaces an account-level Audience Optimization performance view.

• For each campaign that uses Audience Optimization, a randomly selected portion of eligible recipients is automatically held out in a control group. These recipients receive the campaign without optimization, meaning they are not evaluated or excluded by the model.
• The remaining recipients are evaluated by Audience Optimization. Based on model predictions, some recipients may be excluded from receiving the campaign to improve overall performance.
• When reporting performance, we compare outcomes between:
  • The optimized group (where Audience Optimization is applied), and
  • The control group (where no optimization is applied)
• The control group size is automatically managed by Klaviyo and may change over time; you do not need to configure or maintain it.
• Metric impact (e.g., unsubscribe rate, click rate, conversion rate) is calculated as the relative difference between the optimized group and the control group for a given metric. For example, if the unsubscribe rate is 0.07% for the optimized group and 0.08% for the control group, the change is calculated as (0.07% − 0.08%) ÷ 0.08% = −13%, indicating a reduction in unsubscribes.

You can view the overall impact of Audience Optimization across your campaigns directly from the Audience Optimization card by expanding “View impact of audience optimization across all campaigns.”

Metrics include:

• Unsubscribe rate change: How Audience Optimization impacts unsubscribe rates, shown for email, SMS, and WhatsApp campaigns (unsubscribe rate doesn't apply to Push).
• Placed order rate lift: How Audience Optimization impacts the rate of recipients placing an order after a send.
• Statistical significance: An indicator of whether the difference between the optimized and control groups is statistically significant, so you can gauge how much confidence to place in a given result.
• Date range: Choose the reporting window (for example, the last 30, 60, or 90 days). NOTE: Date selector is only enabled you have at least 90 days of campaign history.
• Campaigns evaluated: The number of campaigns with Audience Optimization included in the aggregate analysis.

Campaigns are included in the performance view after a campaign has been finished for at least 24 hours. This buffer lets Klaviyo capture late data automatically, so you don’t need to take any extra steps before checking results.

Identify Audience Optimization campaigns

You can quickly identify and filter campaigns that used Audience Optimization from the campaign list.

• Campaigns sent with Audience Optimization are marked with a ⚡ (lightning bolt) icon in the Campaign type column.

• You can also use the filters in the campaign list to view only campaigns that used Audience Optimization.

Audience Optimization FAQs

What does Audience Optimization optimize for?

Audience Optimization optimizes for campaign performance by removing recipients who are unlikely to engage or convert, or likely to unsubscribe.

The model uses signals related to engagement, conversion, and unsubscribe likelihood to determine which recipients should be excluded from a campaign send.

Which channels support Audience Optimization?

Audience Optimization is available for email, SMS, RCS, WhatsApp, and Push campaigns, as well as omnichannel campaigns that combine multiple channels.

Does Audience Optimization apply to every channel in an omnichannel campaign?

By default, yes. Enabling Audience Optimization at the omnichannel level applies it to all enabled channels in that campaign. You can turn it off for individual channels within the same campaign if you'd like Audience Optimization applied selectively.

Why don't I see the Audience Optimization option for a campaign?

The Audience Optimization toggle can be hidden for several reasons:

• Your account is currently in Reputation Repair, in which case the option is suppressed until your deliverability status improves.
• No audience has been added yet; the option only appears after you select at least one list or segment.

How is this different from suppression?

• Suppression removes profiles from receiving any further campaigns or flows.
• Audience Optimization evaluates a single campaign and removes only the highest‐risk recipients for that send, based on modeled unsubscribe likelihood. Those same recipients might be eligible for different content or future sends.

Why did my Audience Optimization reporting change?

Klaviyo periodically improves the underlying models and infrastructure that power Audience Optimization. When this happens, you may see a notice in your account letting you know that reporting is being updated.

• Historical performance data won't carry over into the new view. If you'd like to keep a record of your current reporting before it updates, take a screenshot and save it locally on your computer.
• New sends are tracked under the updated reporting going forward, so results will continue to accumulate normally after the transition.
• This doesn't affect which recipients are removed from your sends, only how performance is reported.

Additional resources