Frequently asked questions about identity resolution in Klaviyo

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Updated Aug 5, 2025, 12:00 AM EST

Table of contents

• You will learn
• What is identity resolution?
• How profiles are merged
• Profile data
• Flows
• Additional resources

You will learn

Learn about frequently asked questions related to identity resolution in Klaviyo. If you don’t see your question in the resource below, please reach out on our Community forum.

What is identity resolution?

Identity resolution refers to the ability to maintain a single customer record, even when a customer uses different combinations of identifiers and channels over time. This provides a unified view of your customers regardless of how they interact with your brand.

A common example of this is when a customer that has an email profile in your Klaviyo account later subscribes to SMS through a method that is not associated with their email, like a keyword opt-in. This customer action results in a separate profile for receiving SMS messages and a separate profile for receiving emails. However, if this customer later takes an action (like making a purchase) where they submit both their phone and email, Klaviyo recognizes that both the phone and email belong to the same customer and merges the profiles.

Klaviyo’s identity resolution functionality has 2 key components:

• Identity capture Klaviyo’s identity capture functionality automatically cookies and identifies users that click through your email or submit a Klaviyo form, allowing you to capture your customer’s activity on your website.
• Deterministic profile merge Klaviyo resolves customer identities through a proactive check that merges 2 separate profiles when an action occurs linking an email address, phone number, or anonymous mobile app ID (iOS or Android) together. This allows you to manage omnichannel customer data effectively.

How profiles are merged

What is deterministic merging and how is it different from probabilistic merging?

Probabilistic merging is another type of profile merging that ties engagements made by a single user across multiple devices to a unified customer profile. Probabilistic merging uses predictive algorithms to link information, such as IP address, operating system, location, Wi-Fi network, and behavioral data to an individual. This type of merging is often applicable to one-to-many communications and marketing.

Meanwhile, deterministic merging leverages first-party data that customers have provided and unifies their engagements. Engagements are only linked based on information that your customers provide to you directly, prioritizing the accuracy of your customer profiles. This type of merging is critical for one-to-one communication and personalization.

What triggers a profile merge?

For Klaviyo to identify that multiple profiles belong to the same customer and merge them, the identifiers associated with each profile need to be recognized together. Often, this information comes in the form of an event, where the event data includes multiple identifiers like email and phone number.

A common example is a Started checkout event, where the customer provides both their email address and phone number. If there is a separate phone-only profile from a previous action the customer took (e.g., submitting a phone-only form or texting a keyword), Klaviyo will recognize these belong to the same customer and merge them under the profile with the stronger identifier. For more information on identifier precedence, see our guide to understanding identity resolution in Klaviyo.

In addition to merging based on event data, Klaviyo checks if there is an opportunity to merge when customers provide their information through an opt-in method, like a form with phone number and email fields.

Klaviyo also checks for opportunities to merge profiles based on information submitted implicitly through cookie tracking, which associates an activity to an email profile. For example, if an email profile submits a phone-only form with their cookie present, then the phone number they provided will be appended to their pre-existing profile.

Additional examples that would result in a profile merge:

• A phone-only profile provides an email address which matches an existing profile.
• An email-only profile provides a phone number which matches an existing phone-only profile.
• A customer with a separate email-only profile and phone-only profile clicks on a button in an email that directs to a form embedded on your store’s website, and submits their phone number there.
• An email-only profile being tracked through the Klaviyo cookie clicks on an SMS shortened link on the same device and browser.
• A customer with an email-only profile is targeted with an SMS consent form or emailed a link to an SMS consent form. Their form submission can be then traced to their email via cookie, and the phone number will be appended to the pre-existing profile.

What types of events will not trigger a profile merge?

A plain subscribe keyword, including one sent from a tap-to-text banner in an email, does not identify the sender’s email profile. Klaviyo cannot connect the browser cookie to the SMS app from the keyword alone. A Klaviyo tap-to-text form can link the profiles when the visitor is already identified and the prefilled message includes their unique reference. The customer must send that message with the reference intact. Learn more about subscribe keywords.

Examples of cases where profiles would not merge:

• A customer with an email-only profile and phone-only profile uses a tap-to-text link that sends only a subscribe keyword, without a reference identifying their email profile.
• A customer with an email-only profile and phone-only profile sees a keyword call-to-action on an email or targeted banner and texts the keyword.

If separate profiles take cookied actions on the same device and browser, will the profiles be merged?

For a customer with an email-only profile and a phone-only profile, the order of tracked link clicks matters. The profiles can merge when the customer takes these actions in order:

1. Clicks a tracked email link to your website, identifying their browser with their email profile.
2. Clicks a Klaviyo-shortened SMS link in the same browser and on the same device while the email cookie is still present.

Clicking the links in the reverse order does not, by itself, merge an email-only profile with a phone-only profile.

Is it possible the source profile will get re-created if both email addresses are still present in an ecommerce integration?

When a pair of profiles are merged, the source profile is deleted. If Klaviyo later receives an event with the source profile’s original email address and that address is no longer associated with an existing profile, a new profile is created with that email address. If the address is retained on the destination profile, later activity can resolve to that profile instead.

What is a destination vs. source profile?

During the merge process, there are 2 profiles that are consolidated together. One profile is preserved and the other is merged. These profiles are called the “destination” and “source profiles.”

• Destination profile The profile that is preserved during a merge is the destination profile. For automatic merges that link identifiers, this profile has the higher-ranking identifier of the pair of profiles involved in a merge. When you manually merge profiles, you choose the destination profile.
• Source profile The profile that has its data merged into the destination profile is the source profile. For automatic merges that link identifiers, this source profile has the lower-ranking identifier of the pair of profiles involved in a merge.

Profile merges cannot be reversed.

Profile data

What happens to the data on the source profile when it is part of a merge?

When a source profile has merged into a destination profile, a Merged profile event is added to the destination profile. All events from the source profile will migrate into the destination profile as well.

Events appear in the timeline with the original timestamp and are attributed to the destination profile. The destination profile also inherits the list memberships of the merged profile. Note that the destination profile may not meet the same segment criteria as the source profile.

How are profile properties handled when a profile is merged?

Profile properties are added to the destination profile unless each profile has the same property but with different values. In that case, the destination profile’s properties take higher precedence.

There are 2 exceptions:

1. Timezone: Klaviyo uses the source profile’s timezone when it has one. Otherwise, the destination profile’s timezone is kept.
2. Location: Klaviyo will use the location of the source profile if it has more location data (address, city, country, etc.).

Will a profile’s skipped messages be merged as well?

A profile’s skipped messages will merge for both flow and campaign messages and be visible in the Messages tab of the destination profile.

How are consent and exclusion records treated during a profile merge?

A profile merge combines existing subscription information. It does not collect new consent or mean that the customer can receive messages on every channel.

If both profiles use the same email address and only the source profile has an email suppression record, Klaviyo copies that record to the destination profile.

If both profiles have an email suppression record for the same address and the same reason, Klaviyo keeps the earlier suppression date.

For consent records:

• If both profiles use the same email address and only the source profile has an email consent record, Klaviyo uses that record on the destination profile.
• If both profiles have an email consent record for the same address and the same consent status, Klaviyo keeps the earlier consent date.

For example, if both profiles use the same email address:

After merging, review the destination profile’s consent and suppression status on the Details tab before sending messages. Check each channel separately.

Consent is never added to a phone number without explicit consent from that specific phone number.

Would active coupons under the source profile merge over to the destination profile?

The assignment of coupon codes to customer profiles is not altered during a profile merge. Active coupons assigned to the source profile are not reassigned to the destination profile.

Flows

How does profile merging impact list- and segment-triggered flows?

For list- and segment-triggered flows, if either profile has completed or canceled the flow and the other is still active in it, the remaining flow messages are canceled. If both profiles are still active in the flow, the source profile’s flow is canceled, and the destination profile continues uninterrupted.

If the source profile is in a flow that the destination profile is not in, the destination profile takes the place of the source profile in the flow.

How are date-triggered flows affected?

The source profile is merged into the destination profile and the date value that exists on the destination profile would remain. The destination profile then continues to move through the date-triggered flow like normal.

Can a profile still qualify for a list-triggered flow if the merged profile already went through that flow?

For a list-triggered flow set to No re-entry, the source profile’s flow history is retained during the merge and prevents the destination profile from entering again. If the flow allows re-entry, future entry depends on its re-entry criteria and whether the profile meets the trigger conditions.

When profiles are merged, their existing list-triggered flow participation is handled as follows:

1. If the source profile is in the flow, but the destination profile is not, the destination profile takes the place of the source profile in the flow.
2. If the destination profile is in the flow, but the source profile is not, the destination profile continues through the flow uninterrupted.
3. If both profiles have entered the flow:
4. If both profiles are still active in the flow, Klaviyo cancels the flow for the source profile. The source profile record is deleted on merge and the destination profile continues in the flow uninterrupted.
5. If the source profile is in a flow and the destination profile has completed or been skipped for the flow, the flow is canceled for the source profile.
6. If the source profile has completed a flow and the destination profile is in the flow at the time of merge, the flow is canceled for the destination profile.

Additional resources

• Understanding profiles in Klaviyo

Learn about profiles, including how to find them and the data available on the profile page. Profiles are used to keep track of all the information you have about your customers and prospects. - Understanding when SMS profiles merge

Learn how SMS affect profiles in Klaviyo, including how email and phone number contacts merge into one cohesive profile and what unique scenarios are cause for exceptions. - Understanding identity resolution in Klaviyo

Learn about identity resolution in Klaviyo, which consolidates customers’ interactions across multiple channels under a single record.

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