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Klaviyo Integration

Klaviyo is one of the most powerful email and SMS marketing platforms out there, especially for ecommerce brands. But all those sophisticated flows and segments mean nothing if you're sending to invalid email addresses.

With Valid Email Checker's Klaviyo integration, you can verify your subscriber lists and segments directly—no CSV exports, no manual uploads, no headaches. Just connect, select, verify, and your Klaviyo lists are clean.

What You Can Do​

Once connected, you can:

  • Import lists directly from your Klaviyo account
  • See subscriber counts for each list before verifying
  • Verify any list or segment without manual exports
  • Auto-clean your lists by removing or unsubscribing bad emails
  • Connect multiple Klaviyo accounts if you manage several brands
  • Sync anytime to get the latest subscribers

Before You Start​

You'll need:

RequirementDetails
Klaviyo accountAny plan (free or paid)
Valid Email Checker accountWith available credits
Klaviyo Private API KeyWith List and Profiles access (we'll show you how)
About API Keys

Klaviyo uses Private API Keys for integrations. You'll create one specifically for Valid Email Checker with the right permissions. Don't worry—it takes about 2 minutes.

Finding Your Klaviyo Private API Key​

Here's how to create a Private API Key in Klaviyo:

Step 1: Go to API Keys Settings​

  1. Log in to your Klaviyo account
  2. Click your profile icon in the left sidebar
  3. Select Settings
  4. In the left sidebar under Account, click API keys

Klaviyo Settings page showing API keys section with Create Private API Key button

Step 2: Create a New Private API Key​

  1. Click the Create Private API Key button
  2. Give your key a name like Valid Email Checker Integration
  3. Select Custom Key for the access level

Step 3: Set the Required Permissions​

For Valid Email Checker to work properly, you need to enable Full Access for these scopes:

ScopeAccess LevelWhy It's Needed
AccountsFull AccessTo identify your Klaviyo account
ListFull AccessTo read your lists and modify subscribers
ProfilesFull AccessTo access and update contact information

Klaviyo API key creation showing Custom Key selected with Accounts, List, and Profiles set to Full Access

Required Permissions
ScopeMinimum Access
AccountsEither Full or Read Access
ListFull Access
ProfilesFull Access

List and Profiles need Full Access so we can clean your lists automatically. Read Access alone won't work for these.

Step 4: Copy Your API Key​

  1. Click Create to generate the key
  2. Copy the key immediately—Klaviyo only shows it once!
  3. Store it somewhere safe if you need it later

Connecting Klaviyo to Valid Email Checker​

Now let's connect your Klaviyo account:

Step 1: Open the Integration​

Option A: Go to Integrations in the sidebar and click Klaviyo

Option B: Go to Bulk Upload and click Connect Email Platform, then select Klaviyo

Step 2: Enter Your Details​

Valid Email Checker connection modal for Klaviyo asking for connection name and Private API Key

FieldWhat to Enter
Connection NameA friendly name like "My Klaviyo Account" or your brand name (optional)
Klaviyo Private API KeyPaste the API key you just created

Step 3: Connect​

Click Connect Account. We'll verify your API key and sync your lists.

Quick Connection Test

Once connected, you should see your Klaviyo lists with subscriber counts within a few seconds. If nothing appears, double-check that your API key has the correct permissions.

Verifying Your Klaviyo Lists​

Once connected, you can verify any list in your Klaviyo account.

Step 1: Select Your List​

Go to Bulk Upload and click Connect Email Platform. Select your Klaviyo connection.

Klaviyo list selection showing available lists with subscriber counts and verification options

You'll see all your Klaviyo lists with subscriber counts, Select the list you want to verify.

Step 2: Choose Your Verification Mode​

Option A: Verify Only

We import and verify your emails, but don't make any changes to your Klaviyo list. Perfect when you want to review results first.

Option B: Clean List Automatically

We verify AND automatically clean your list based on your settings:

Email TypeOptionsDefault
InvalidKeep / Unsubscribe / DeleteUnsubscribe
DisposableKeep / Unsubscribe / DeleteDelete
Catch-allKeep / Unsubscribe / DeleteKeep
UnknownKeep / Unsubscribe / DeleteKeep
RiskyKeep / Unsubscribe / DeleteKeep

Step 3: Start Verification​

Click Import List to start. You'll be redirected to the Uploads & Results page to track progress.

Monitoring Your Verification​

After starting verification, you can track progress in real-time.

Uploads & Results page showing completed Klaviyo verification with 250 emails processed

The results table shows:

ColumnDescription
Task IDUnique identifier (e.g., VECK6AVRRST)
List NameYour list name with HubSpot icon
Upload DateWhen verification started
Total EmailsNumber of contacts being verified
StatusProcessing, Completed, Failed, or Deleted
ProgressPercentage complete
ActionsView Results when done

Estimated Verification Times​

List SizeEstimated Time
100 emailsSeconds
1,000 emails1-2 minutes
10,000 emails5-10 minutes
100,000 emails15-30 minutes
1,000,000 emails1-2 hours

When complete, click View Results to see the breakdown and download your verified data.

Managing Your Klaviyo Connection​

Find all your connections on the Integrations page.

Integrations page showing connected Klaviyo account with three-dot menu options

Available Actions​

Click the three-dot menu (⋮) for any connection:

ActionWhat It Does
Sync NowRefresh your lists to get the latest subscribers
RenameChange the connection name
DeleteRemove the connection entirely

When to Sync​

Hit Sync Now when:

  • You've added new subscribers in Klaviyo
  • You've created new lists or segments
  • Subscriber counts seem outdated
  • You want to verify recently added contacts

Connecting Multiple Klaviyo Accounts​

Managing multiple brands or client accounts? You can connect them all.

Multiple Klaviyo connections showing option to sync existing or add another account

Adding Another Account​

  1. Go to Bulk Upload → Connect Email Platform → Klaviyo
  2. You'll see your existing connections listed
  3. Click Add Another Account
  4. Enter a unique name (e.g., "Brand B - Klaviyo")
  5. Paste the API key from your other Klaviyo account
  6. Click Connect Account
Unique API Keys Required

Each Klaviyo account needs its own Private API Key. You can't use the same key for multiple accounts.

Managing Multiple Connections​

When verifying, you can choose which account to use. Each connection shows:

  • Connection name
  • When it was connected
  • Sync Now button for quick updates

Troubleshooting​

"Invalid API Key" Error​

Causes:

  • Typo when pasting the key
  • Key was deleted in Klaviyo
  • Key doesn't have required permissions

Fix:

  1. Go back to Klaviyo → Settings → API Keys
  2. Create a new Private API Key
  3. Make sure Accounts, List, and Profiles all have Full Access
  4. Copy and paste carefully (no extra spaces)

No Lists Appearing​

Causes:

  • API key only has Read Access (needs Full Access)
  • Klaviyo account has no lists yet
  • Connection issue

Fix:

  1. Verify your API key has Full Access for List scope
  2. Check that you have at least one list in Klaviyo
  3. Click Sync Now to refresh

Can't Connect Multiple Accounts​

Causes:

  • Using the same API key for both
  • Connection name already exists

Fix:

  1. Each Klaviyo account needs its own unique API key
  2. Use different connection names (e.g., "Brand A" and "Brand B")

Verification Taking Too Long​

Causes:

  • Very large list
  • High server load

Fix:

  • Large lists naturally take longer—check the timing estimates above
  • The progress bar updates in real-time, no need to refresh
  • For lists over 100,000, expect 15-30+ minutes

Changes Not Reflecting in Klaviyo​

Causes:

  • You selected "Verify Only" instead of "Clean List Automatically"
  • Klaviyo's interface may cache data

Fix:

  1. If you chose "Verify Only," changes don't sync back—that's expected
  2. Refresh your Klaviyo page or wait a few minutes
  3. Check the profile status in Klaviyo directly

Frequently Asked Questions​

How often should I verify my Klaviyo lists?​

For active ecommerce stores, we recommend:

  • Monthly for your main newsletter list
  • Before every major campaign (Black Friday, launches, etc.)
  • Quarterly for less active segments

Does this work with Klaviyo segments?​

Yes! Segments appear alongside lists. Just remember that segments are dynamic—new subscribers matching your segment criteria will be added automatically (and they won't be verified yet).

Will verification affect my Klaviyo flows?​

No, verification doesn't change your flow logic. It only affects individual profile statuses (subscribed → unsubscribed) if you choose "Clean List Automatically."

Can I verify my entire Klaviyo database at once?​

Yes, but we recommend verifying by list or segment for better control. If you have one master list with everyone, you can verify that.

Is my Klaviyo data safe?​

Absolutely. We only read your lists and profiles to verify emails. We don't store your contact data permanently, and everything is deleted after 15 days. See our Data & Privacy Policy for details.

Next Steps​

Need Help?​

Running into issues with your Klaviyo integration? We're here to help: