Linking Klaviyo Profiles and LINE Friends by ID

ID linkage ties a Klaviyo profile and a LINE friend together as the same person, and setting it up correctly is the foundation of the Klaviyo integration.

What is ID linking?

ID linkage is the mechanism that ties a Klaviyo profile and a LINE friend in Lumo together as the same person.

The link is made using one of three signals: an email address, a phone number, or a LINE User ID. Once ID linkage is complete for a customer, you can use everything that depends on it: syncing profile data, sending LINE broadcasts from Klaviyo Flows, and recording LINE activity back to Klaviyo. Conversely, none of these features apply to customers who are not yet linked. ID linkage is the foundation you want to get right first in order to make the most of the Klaviyo integration.

Choosing an ID linking method

There are several ways to set up ID linkage, each suited to a different customer journey, so pick the one that fits your goal.

If you are unsure which methods to combine, ask the Marketing Agent, "Please help me set up the Klaviyo integration," and you can work out the approach that best fits your operations together.

Linking from email with a custom QR Code

You can embed a per-customer linking QR Code in your Klaviyo emails and trigger ID linkage when the customer adds you as a friend.

When you set Klaviyo as the link type on a Lumo custom QR Code, you can tie an existing Klaviyo profile to a LINE user based on the email address. The setup steps are as follows.

1. Create a custom QR Code in Lumo, and in the "ID Linking" section set "Integration type" to "Klaviyo Integration"
2. As the signal for linking, specify the Klaviyo merge variable that contains the customer's email address
3. Once you save the settings, a linking URL is issued, so reopen this screen to check the URL
4. Embed the issued URL or QR Code in your Klaviyo email and send it

When a customer who receives the email clicks the link or scans the QR Code and adds you as a friend, the matching Klaviyo profile and LINE user are tied together automatically based on the email address.

When the linking URL doesn't appear

The linking URL is issued after you save the settings. If it is not yet displayed, save once, then reopen the custom QR Code edit screen to check.

Linking IDs from form submissions

You can trigger ID linkage by showing a LINE link button when a Klaviyo form is submitted.

You configure this under "Link IDs from Form Submissions" on the "ID linkage" tab of the Klaviyo integration. The steps are as follows.

1. Under "Target form", choose the Klaviyo form to use for linking
2. In "CTA label", enter the text to show on the link button (for example, "Link with LINE")
3. Add the "Landing page install code" to the landing page where the Klaviyo form is placed. This carries the form's submission details over to LINE linkage on the Success screen. On a Shopify store, turn on "Lumo LINE CTA" under "App embeds" in the theme editor instead of adding the code
4. Add a Button block to the Success screen of the Klaviyo popup form, and set the "Success screen button URL" in "Go to URL"

After setup, when a customer submits the form, the button on the Success screen switches to the linking display. On smartphones a LINE link button appears, and on computers a QR Code appears; when the customer adds you as a friend, ID linkage is performed based on the email address or phone number entered in the form.

Choosing what to show on the Success screen

You choose what Lumo shows on the Success screen in "What to show on the Success screen". If you've designed the Success screen carefully and don't want Lumo's guidance there, choose "QR code only".

When you choose "QR code only", write a line that invites customers to add you as a friend on the Klaviyo Success screen (for example: Add us as a friend on LINE and we'll send you a coupon). Once linking is done, a single line, "LINE connected", appears where the QR Code was, in the form's own font and color.

Changing the copy for QR code with guidance

When "QR code with guidance" is selected, you can change the copy Lumo shows for each language in "Copy for QR code with guidance". Fields you leave blank keep Lumo's default copy.

Switch "Language to edit" to enter copy in Japanese, English, Traditional Chinese, and Thai. Customers see the language of their browser. The title and description aren't shown when left blank. Check how your copy looks on PC and smartphones in "Preview".

Turning on the app embed on a Shopify store

For a Klaviyo form on a Shopify store, you just turn on Lumo's app embed instead of adding the "Landing page install code". You don't need permission to edit the theme code. Your Shopify integration must be connected to the same LINE Official Account as Klaviyo.

1. In Shopify admin, open "Online Store" > "Themes" > "Customize"
2. Open "App embeds" in the left panel and turn on "Lumo LINE CTA". Make sure "Show LINE CTAs / LINEのCTAを表示する" inside it is also on
3. Click "Save"

On a Shopify store, you still set the "Success screen button URL" on the Success screen of the Klaviyo popup form. If you haven't created any CTAs in Lumo, turning on the app embed doesn't change how your store looks.

Deciding the response and destination after linking

You can decide what LINE sends and where the customer goes once an identity link through a form completes. Set it under "Response after linking" in "Link IDs from Form Submissions".

There are three choices for "Response type".

In "Redirect URL after linking (optional)", specify the page you want the customer to open once linking is done. Enter a URL starting with http or https. If you leave it unset, the LINE chat screen opens after linking.

It works the same way as the response you set for QR Code identity linking. Use it when you want to deliver a thank-you or a coupon for linking right on the spot.

How mismatches are prevented

When both an email address and a phone number are available as signals, Lumo links them only when both match within the same profile. This mechanism prevents information from different people from accidentally being mixed together and linked.

Controlling form submission timing with a Flow

If you want to control the timing of form submission with a Klaviyo Flow, use "Post-submission link setup" under "Link IDs from Form Submissions". Create a Flow for the selected form, and set the "Link URL" and "Request body" shown in the Webhook action.

Choose the Flow trigger to match your operations. To link immediately after the form is submitted, you can use "Submitted Form"; to link after double opt-in is completed, you can use "Subscribed to List", for example.

When the link button doesn't appear

If the link button doesn't appear after the form is submitted, check the following two points.

• Whether the "Landing page install code" is correctly added to the landing page. On a Shopify store, whether "Lumo LINE CTA" is turned on under "App embeds" in the theme editor
• Whether the "Success screen button URL" is set on the Button block of the Success screen

Linking IDs from Flows

Triggered by an existing Klaviyo Flow, you can automatically match LINE friends by email address and set up ID linkage.

Under "Link IDs from Flows" on the "ID linkage" tab of the Klaviyo integration, check the settings for the Webhook action to add to your Klaviyo Flow. The steps are as follows.

1. Add a "Webhook" action to the Klaviyo Flow you want to use as the trigger (for example, a Flow that runs after double opt-in completes)
2. Choose "POST" as the HTTP method and set the "Destination URL"
3. Set the displayed Key and Value in the custom header
4. Paste the displayed content into the "JSON body"

The email in the JSON body is used to match a LINE friend, linking the Klaviyo profile and the LINE friend. To also match by phone number, add phoneNumber. Only friends whose email address or phone number is already known are linked.

This is handy when you want to reliably link customers who are already LINE friends at the moment of an email-driven action, such as a subscription or a purchase.

Linking IDs from a Segment

If LINE User IDs are already stored in Klaviyo, you can read them and set up ID linkage.

You configure this under "Link IDs from Segments" on the "ID linkage" tab of the Klaviyo integration. The steps are as follows.

1. Under "Source segment", choose the Klaviyo Segment that contains the profiles holding LINE User IDs
2. Under "LINE User ID property", select or enter the Klaviyo property where the LINE User ID is stored

Once you specify a source Segment, existing LINE User IDs are imported from Klaviyo every 15 minutes and tied to your Lumo friends. If you remove the specification, the import stops. This is handy when LINE User IDs are already managed in Klaviyo, such as during a migration from another vendor's tool.

Auto-linking by email or phone number

ID linkage also happens automatically based on email address or phone number as part of normal data sync.

When LINE friend information is synced to Klaviyo, if a Klaviyo profile with a matching email address or phone number is found, it is tied automatically. The matched profile gets a LINE User ID written to it and is treated as the same person from then on. No special setup is required; this works automatically as long as the integration is enabled.

When a Klaviyo form submission or a Klaviyo flow leads to an identity link, you can automate a thank-you or a perk with the Workflow "Identity Linked" trigger.

Importing ID links in bulk

You can import LINE friend–Klaviyo profile links in bulk from ID links made with other tools or from a CSV file.

Under "Import from a CSV File" on the "ID linkage" tab of the Klaviyo integration, upload a CSV file with two columns: email address and LINE User ID. The steps are as follows.

1. Drag and drop the CSV file (up to 50MB, with a header row on the first line), or upload it with "Select file"
2. In "Email column" and "LINE User ID column", choose the corresponding CSV columns
3. Choose "Start import"

Imported links propagate to Klaviyo and Shopify (when connected). To bring links into HubSpot, use "Link IDs from Segments" in the HubSpot integration settings. After the import, you can review the per-row results on screen (linked, not a friend, invalid format, duplicate, failed). Only customers who are already LINE friends are linked, and rows for people who are not yet friends are not imported. If more people become friends later, run the import again to bring them in.

Automatically importing link data that another LINE integration tool stored on Shopify customers is done under "Link IDs from Segments" on the "ID linkage" tab of the Shopify integration.

Checking the link status

You can check ID linkage status on the "ID linkage" tab of the Klaviyo integration, on the friend's detail screen, and from Segment conditions.

"Linkage status" at the top of the "ID linkage" tab brings together the number of linked friends, when the last link happened, and how many new links there were in the last 30 days. It is the place to start when you want to see how linking grew after a campaign.

On the friend's detail screen, you can check the linkage status under "Klaviyo Sync Info", and open the profile on the Klaviyo side from "View on Klaviyo". If a friend got linked to the wrong profile, you can remove just the Klaviyo link from "Unlink identity" under "More actions" on the same screen. An unlinked friend isn't linked again by automatic email matching. See Unlinking an identity for the steps.

When you want to filter customers by whether they are linked, use Segments. If you choose the condition "Klaviyo ID linked" when creating a Segment, you can pull up linked and unlinked customers separately. Note that what you use here is a Segment, which is a filtering condition for friends. It is a different concept from a friend's tag, so be careful not to confuse them. If many customers are unlinked, it is a good idea to point them to additional ID linkage methods.

When things don't work

Common ID linkage issues and how to address them are listed below.