Subi's Klaviyo integration keeps your subscription audience in sync with Klaviyo. Once connected, Subi automatically sends your subscription customers' email addresses to a dedicated Klaviyo list, so you can build segments, campaigns, and flows around the people who subscribe to your store — without exporting and importing lists by hand.
What the integration does
When you connect Klaviyo, Subi:
Creates (or reuses) a Klaviyo list named Subi in your Klaviyo account.
Adds every existing subscription customer's email to that list as a Klaviyo profile.
Keeps the list up to date — whenever a new customer subscribes in your store, Subi adds them to the Subi list automatically.
If a customer already exists in Klaviyo, Subi matches them by email and updates the existing profile instead of creating a duplicate.
Good to know: Subi syncs the customer's email address so Klaviyo can recognize the profile and add it to the Subi list. To bring in richer data — like order history, products purchased, or subscription events — use Klaviyo's own Shopify integration alongside Subi. Subi gives you the subscriber audience; Klaviyo's Shopify connection gives you the order and event data to personalize your messages.
Before you start
You'll need:
A Klaviyo account connected to the same store.
A Klaviyo Public API Key and Private API Key. The private key must have Profiles → Full Access permission (or be created as a Full Access key). Without this permission, the sync won't work.
The Klaviyo integration is available on plans that include it. If you don't have access yet, you'll see an option to upgrade when you open the integration page.
Step 1: Get your Klaviyo API keys
Log in to Klaviyo and go to Settings → API Keys (under Account).
Copy your Public API Key (also called your Site ID) from the top of the page.
Select Create Private API Key.
Give the key a name you'll recognize, such as "Subi".
Set the access level so the key has Profiles → Full Access — either choose Full Access or create a Custom key with Full Access to Profiles. This lets Subi create profiles and add them to a list.
Select Create and copy the private key. Keep it somewhere safe — Klaviyo only shows it once.
Step 2: Connect Klaviyo in Subi
In your Subi admin, go to Settings → Integrations.
Find the Klaviyo card and select Configure.
Paste your Public API Key and Private API Key into the matching fields.
Select Connect to Klaviyo.
Once connected, the Klaviyo card shows an Active badge, and Subi immediately begins syncing your existing subscription customers to the Subi list in Klaviyo. Large stores may take a little time to finish the first sync.
Step 3: Use the Subi list in Klaviyo
With your subscribers flowing into the Subi list, you can:
Build a segment of subscribers — for example, "everyone in the Subi list" — and send them targeted campaigns.
Trigger a flow when a profile is added to the Subi list, such as a subscriber welcome series.
Combine the Subi list with the order and product data from Klaviyo's Shopify integration to personalize messages — for example, a flow that targets Subi list members who bought a specific product.
Because Subi adds profiles to a list, make sure you have permission to email these customers and that you follow Klaviyo's consent rules before sending marketing messages.
Updating or disconnecting
To update your keys, return to Settings → Integrations → Klaviyo, enter the new keys, and select Update.
To stop syncing, open the same page and select Disconnect. Subi stops sending new subscribers to Klaviyo. Profiles already added to the Subi list stay in your Klaviyo account.
Troubleshooting
The integration turned itself off. If your API key is invalid or doesn't have the required permissions, Subi deactivates the connection automatically. Re-check that your private key has Profiles → Full Access, then reconnect with a valid key.
"Failed to connect" message. Double-check that you copied the full public and private keys with no extra spaces, and that the keys belong to the correct Klaviyo account.
My subscribers aren't in Klaviyo yet. The first sync runs right after you connect and can take a little while on larger stores. New subscribers are added as they subscribe.
Need a hand?
If your subscribers still aren't syncing after checking your API key permissions, reach out to our support team from the Help Center and we'll take a look.