How to integrate with Segment

How to integrate with Segment

Estimated 4 minute read

Updated Jul 30, 2025, 12:00 AM EST

Table of contents

You will learn
Before you begin
Connect Segment and Klaviyo
Segment metrics
Monitoring the Klaviyo sync
Outcome
Additional resources

You will learn

Learn how to integrate Segment with Klaviyo to be able to trigger and filter flows, and define segments using events synced to Klaviyo from your Segment project. Use the Klaviyo (Actions) destination to send track events and identify profile updates from Segment to Klaviyo.

This guide covers sending Segment data to Klaviyo and, optionally, sending Klaviyo email activity back to Segment. For the destination configuration, use Segment's comprehensive guide to integrating with Klaviyo.

Before you begin

Use consistent customer identifiers across Segment and Klaviyo. When sending email activity back to Segment, Klaviyo uses the Segment user ID or anonymous ID stored on each profile.

If a profile has neither Segment identifier, Klaviyo uses its email address as an anonymous ID when sending email activity to Segment. This can create a separate identity in Segment. You can exclude these profiles using the setting in Enable the integration in Klaviyo below.

Connect Segment and Klaviyo

Add Klaviyo (Actions) as a destination in Segment

Follow Segment's Klaviyo (Actions) setup guide to add the destination and connect the Segment source whose data you want to send to Klaviyo.

Configure the destination and its action mappings using Segment's guide and the Klaviyo details below.

A private Klaviyo API key with full access to Accounts, Campaigns, Events, Lists, Profiles, Segments, and Subscriptions. Learn how to create a private API key and how to manage your API keys in Klaviyo.
If you want to add profiles to a list, use that list’s ID in the relevant action mapping. Learn how to find your List ID in Klaviyo.

Treat private API keys like passwords kept in a safe place and never exposed to the public.

Use Upsert Profile for identify calls that create or update profile information, and Track Event for track calls that record customer activity. Follow Segment's guide to configure and enable the mappings you need.

Enable the destination in Segment to start sending data that matches your enabled mappings.

Send Klaviyo email activity to Segment (optional)

The return sync sends email delivery, open, link click, bounce, spam report, and unsubscribe events to Segment.

Get a write key for the Segment source that should receive your Klaviyo email activity. You can set up a Klaviyo source or find the write key for an existing event streams source.

Copy your Write Key. Your write key is another private API key. Treat it like a password; keep it in a safe place and never expose it to the public.

Enable the integration in Klaviyo

In Klaviyo, select the Integrations tab.
Select Explore apps, search for Segment, and then click the card. Then, click Install.
Paste the write key you copied earlier into the box and choose your Segment region, then click Connect to Segment.
Choose United States if your Segment URL is: <https://app.segment.com/>.
Choose European Union if your Segment URL is: <https://eu1.app.segment.com/>.

On the next page, you can limit the email activity sent back to Segment by checking the box next to Do not sync profiles that are not updated by the Klaviyo Destination.

This setting controls the return sync. It does not merge or remove profiles in Klaviyo. If you leave it unchecked, profiles without stored Segment identifiers send email activity using their email address as an anonymous ID in Segment.
Select the checkbox to send email activity only for profiles with a stored Segment user ID or anonymous ID. Eligibility depends on these identifiers, not where the profile was first created.
Once finished, click Complete setup.

After sending an email from Klaviyo, check the receiving source in Segment for email activity. See Segment’s Klaviyo source guide for the events to expect.

Segment metrics

We recommend syncing the most important events to Klaviyo, such as:

When a customer signs up
When a customer starts to checkout or expresses interest in paying
What a customer buys (including pictures of items and descriptions of items)

Provide the profile identifiers required by your Klaviyo (Actions) mapping, such as an email address or external ID. For detailed information on identifiers and event formatting, see Segment's Klaviyo integration guide.

For transactional web businesses and ecommerce platforms, we recommend following our guide to integrating a custom ecommerce cart or platform for detailed information on the events that should be sent to Klaviyo through Segment.

Monitoring the Klaviyo sync

Once you enable the Klaviyo (Actions) destination and its mappings in Segment, your identify and track calls will begin sending data to Klaviyo within 5-10 minutes. To verify the event sync, send a test track event, then go to Analytics > Metrics in Klaviyo to find the corresponding metric.

For Track Event, the Metric Name mapping determines the metric name in Klaviyo. Klaviyo treats Segment metrics as third-party API metrics, so each metric will have a gear icon next to its name in Klaviyo. To view the incoming data, open the metric and select Activity feed.

To verify an identify call sent through Upsert Profile, check the corresponding Klaviyo profile for the updated information. Profile updates do not create a metric or an event in the metric’s activity feed.

Outcome

You've now integrated Segment with Klaviyo and can start using Segment data to trigger and filter flows, and define segments using events synced to Klaviyo from your Segment project.

Additional resources

Getting started with flows

Learn how to use flows, also known as automations or drip campaigns, in Klaviyo for personalized and automated communications to your customers, and learn how to set your first flow live. - Getting started with segments

Learn how to create and use segments in Klaviyo, which are a powerful tool for understanding your audience and sending targeted messages.

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