Connect your Klaviyo account so contacts can sync to your email platform automatically.
Connection options
You can connect Klaviyo using OAuth (easiest — no keys to manage) or an API key. Both work the same way once connected.
Option 1: OAuth (recommended)
Log in to Retention.com
Go to Settings → Integrations → Klaviyo
Select the OAuth tab and click Connect
Authorize via Klaviyo's consent screen
Select the list to sync contacts to — the Retention list is pre-selected by default (recommended)
Click Finish Setup
Option 2: API key
You'll need a private Klaviyo API key with full access permissions.
Log in to Retention.com
Go to Settings → Integrations → Klaviyo
Select the API key tab
Enter your private API key
Select the list to sync contacts to — the Retention list is pre-selected by default (recommended)
Click Finish Setup
Avoid paying for contacts you already have
By default, we check your existing audience in Klaviyo before adding new contacts.
This helps make sure you don't pay for contacts you already have.
How contacts sync to Klaviyo
Once connected and your script is live, contacts will begin syncing to Klaviyo automatically.
They will appear in your account and be organized for sending.
What to do next
→ Learn how contacts sync to your email platform: How Contacts Sync to Your Email Platform
→ Learn how to start sending: What Should I Email My Contacts - Klaviyo