Multi Email Profiles
What are Multi-Email Profiles?
Multi-Email Profiles (MEP) is a Klaviyo feature that lets you store and manage up to 5 email addresses on a single customer profile. When these addresses are linked to the same profile, you can see the customer's activity in one place.
This means better personalization, cleaner analytics, and more consistent experiences across every channel you use.
This guidance applies to accounts with Multi-Email Profiles enabled.
Why does this matter?
Your customers don't stick to one email address. They might sign up with their personal Gmail, check out with a work address, and click a link from a third address they use for shopping. If these addresses aren't linked to the same profile, their interactions can be spread across separate profiles, leading to:
- Duplicate profiles cluttering your account
- Broken automation flows and missed triggers
- Inconsistent consent and suppression records
- Fragmented data that makes personalization harder
- Inflated contact counts and skewed analytics
MEP helps address this by keeping up to 5 of a customer's linked email addresses under one profile.
How email addresses are added and combined
Ways to add email addresses
Klaviyo uses shared identifiers to connect data that belongs to the same person. For example, an update can link a new email address to an existing profile through its External ID, a unique identifier your store or integration provides to Klaviyo, such as a customer ID from your ecommerce platform.
You can add email addresses to a profile in the following ways:
- Automatic identity resolution: When an update matches an existing profile by External ID and provides a new email address, Klaviyo can retain the previous address as a secondary email.
- Klaviyo UI: You can manually add secondary email addresses directly on the profile page in Klaviyo.
- Update Profile API: Developers can use API revision 2025-01-15 or later to add secondary emails programmatically. Multi-Email Profiles must be enabled for the account.
Add an email on a profile
The profile must already have a primary email address before you add a secondary address.
If the profile already has 5 email addresses, remove an existing address before adding another.
- Open the profile and select the Details tab.
- In the Email section, click Add email.
- Enter the address in the Email field, then click Add email. The address appears in the profile's email table.
What carries over when profiles merge?
When profiles merge, Klaviyo designates one as the destination profile, which keeps its Primary Email and identity. The following data can carry over from the other profile:
- Additional email addresses (up to the 5-email cap)
- Profile properties, including custom properties that are not already set on the destination profile
- Event history and activity
- Consent and suppression records
Important: Each email address keeps its own consent and email-specific suppression status after a merge. Subscribing or unsubscribing one email does not affect the others. A manual suppression of the profile applies to all its email addresses.
What happens when a profile already has 5 emails?
Each profile can hold a maximum of 5 email addresses: 1 primary and up to 4 secondary addresses. What happens at the limit depends on how the address is added:
- On the profile page, remove an existing address before adding another.
- Automatic updates can change the primary email and retain the previous address as a secondary. If an accepted update exceeds 5 addresses, Klaviyo removes older secondary addresses, giving priority to addresses that were added or re-added more recently.
- When 2 profiles merge, Klaviyo keeps the destination's primary email. For the 4 secondary slots, it prioritizes the other profile's primary email, then the destination's secondary emails, then the other profile's secondary emails. Within each group of secondary emails, newer addresses take priority.
How Klaviyo picks the Primary Email
A profile with email addresses has 1 Primary Email. Campaigns and flows without an event email use this address. When Klaviyo automatically re-evaluates the primary email, it uses the following rules:
Step 1 — Consent
Klaviyo prioritizes subscribed addresses that are not suppressed, followed by addresses that have never subscribed, then unsubscribed addresses, then suppressed addresses. Being the Primary Email does not grant consent or remove a suppression.
Step 2 — Engagement
If multiple addresses have the same highest consent priority, Klaviyo checks the profile's most recent Placed Order or non-bot email click from the past 30 days. If that event's email is one of the tied addresses, it becomes the Primary Email.
Step 3 — Fallback
If recent activity does not resolve the tie, Klaviyo keeps the current Primary Email if it has the highest consent priority. Otherwise, it selects another address with that priority.
When does the Primary Email update?
The Primary Email can change automatically or when you select another address on the profile.
Automatic updates:
- An email address's consent status changes
- An email address bounces or becomes invalid
Manual updates:
- In the Email section of a profile, open a secondary address's row menu and select Make primary. The previous primary becomes a secondary address. Later consent or deliverability changes can cause Klaviyo to re-evaluate this choice.
Which email address gets the message?
Send type | Which email gets the message |
|---|---|
Campaigns | Campaigns sent to lists or segments use each profile's Primary Email, subject to consent and suppression checks. Secondary emails are not included in campaign sends. |
Event-triggered flows | For flows triggered by events (like an abandoned cart flow), Klaviyo uses the email address associated with the triggering event. If no event email is available, it uses the Primary Email. |
Other flows | List-triggered, segment-triggered, and date-triggered flows use the Primary Email. |
Example: Abandoned cart
Your customer starts checkout using their work email and leaves without purchasing. If the event that triggers your abandoned cart flow includes their work email, Klaviyo sends the flow email to that address, even if their Primary Email is different.
If that event email is unsubscribed or otherwise unable to receive marketing, Klaviyo skips the marketing email send. It does not try another address on the profile. Transactional emails use separate consent checks.
Frequently asked questions
How does MEP get created?
Profiles can gain additional email addresses through identity resolution, the profile page, or the API.
- Automatic identity resolution via External ID: An update that matches an existing profile by External ID and provides a new email can retain the previous email as a secondary address.
- Manually through the Klaviyo UI: You can add a secondary email from the Email section of a profile that already has a primary email address.
- Via the Update Profile API: Developers can add secondary emails using API revision 2025-01-15 or later when Multi-Email Profiles is enabled for the account.
Automatic identity resolution does not require a separate confirmation.
Does having multiple emails on a profile affect my bill?
Billing is based on profiles, not individual email addresses. A profile with 3 email addresses still counts as 1 contact toward your plan.
In fact, MEP can help reduce your billable contact count. If you previously had duplicate profiles for the same customer using different email addresses, merging them into one MEP profile removes those duplicates — meaning fewer contacts overall.
What happens if the Primary Email is unsubscribed or unreachable at send time?
For campaigns: Klaviyo sends only to the Primary Email. If it's unsubscribed or unreachable at send time, that profile is skipped entirely. Klaviyo will not fall back to a secondary email.
For event-triggered flows: Klaviyo uses the triggering event's email, or the Primary Email if no event email is available. If the chosen address cannot receive marketing, the marketing email send is skipped without trying another address. Transactional emails use separate consent checks.
What happens if I try to add more than 5 emails to a Profile?
Behavior depends on how you add the addresses.
Bulk API
Each profile supports a maximum of 5 email addresses (1 primary and up to 4 secondary). Each request to append or remove secondary emails accepts up to 4 addresses per operation. For accepted updates that exceed the stored limit, older secondary addresses can be removed to keep the profile within the cap.
Profile page
When manually adding emails in the UI, a banner will prompt you to delete an existing email before adding a new one.
List imports and SFTP
Keep each profile's email addresses together in one row rather than using repeated rows to add addresses. Within an import batch, rows with identical identifiers can replace earlier rows, while conflicting rows that identify the same profile can be rejected. Check the import errors before retrying.