How to Clean a Klaviyo List: Suppress, Verify and Sunset

To clean a Klaviyo list, let Klaviyo's automatic suppression handle addresses that have already bounced, then deal with what it cannot see: export the segments you have not mailed recently and verify them, bulk-suppress the invalid addresses with a CSV upload, and run a sunset flow for profiles that receive email but never engage. Suppress rather than delete, so the record stays.

Everything below comes from Klaviyo's help centre, read in October 2026. Stopping bad addresses at checkout and signup is covered in email verification for ecommerce stores; this post is about the list you already have.

What Klaviyo already does for you

Klaviyo suppresses hard bounces immediately and repeat soft bounces after seven in a row, so you never need to clean those by hand. The rules, from its bounce handling article and its guide to suppressed profiles:

Event	What Klaviyo does
Hard bounce	"Klaviyo automatically suppresses any email address that hard bounces."
Soft bounces	Suppressed if an address soft bounces "more than 7 consecutive times". Only soft bounces in the past 2 years count.
Spam complaint	Suppressed, with the reason "Spam complaint"
Your own upload	Suppressed with the reason "User suppressed"
Suppressions synced from a previous provider	Imported as suppressions, for example from Mailchimp

A suppressed profile is removed from its lists and cannot receive marketing email. Two details matter:

• Deliverability suppressions are permanent from your side. Klaviyo says suppressions due to hard bounces "are not removed by subscribe actions in order to protect your sender reputation", and bounce suppressions cannot be removed manually.
• Manual suppressions are not. A "User suppressed" profile is lifted if the person resubscribes, which is what you want if a real person re-enters the address.

You can see the full list under Profiles, using the Suppressed Profiles button, and per list from Manage List > List Suppressions.

What Klaviyo cannot do

Klaviyo only learns an address is dead when it bounces, so every address you have never mailed, or not mailed lately, is unchecked. Its bounce article recommends double opt-in at signup and stops there. That leaves three gaps:

1. Imports. A CSV from a trade show, an old Shopify export or a migration has never been mailed from Klaviyo. The first campaign is when the bounces land.
2. Dormant profiles. Subscribers left out of your regular segments for years. Addresses close in the meantime, and nothing tells Klaviyo until you send.
3. Deliverable but silent profiles. These never bounce, so suppression never touches them. Some long-abandoned addresses end up as recycled spam traps.

Klaviyo's deliverability benchmarks call a bounce rate under 1% healthy and over 2% "needs attention". One send to an unchecked import can cross that line, and the bounces count against your domain before anything is suppressed.

Step 1: Export the segments you are about to mail

Export only the profiles that are subscribed and have not been mailed recently, then verify that file. Profiles Klaviyo already suppressed need no checking.

Klaviyo's export guide gives the path: Audience > Lists & segments, open the list or segment, then Manage list > Export list to CSV (or Manage segment > Export segment to CSV). Exporting only Email is faster. Exports appear under Settings > Other > Downloads for 30 days. Only users with the Owner, Admin or Analyst role can export.

Worth exporting: imported profiles that have never received an email, subscribed profiles not mailed in six months or more, and anything joining a large campaign for the first time.

Step 2: Verify the file outside Klaviyo

Run the export through a verifier that checks MX records and talks to each mail server, and split the result into valid, invalid and risky. Klaviyo has no built-in mailbox check, so this is the one step that happens elsewhere.

Leave valid profiles alone. Invalid ones go back in as suppressions in Step 3. Risky results are mostly catch-all domains, which accept every address so nothing outside the company can confirm one. Do not suppress those by default; segment them and send to them separately, in smaller batches.

SimpleVerifier takes CSV uploads up to 100,000 rows and returns a results file with email, status and reason columns, so the invalid rows can be filtered out in a spreadsheet in one step. To spot-check a few addresses first, the free single-address checker shows the result and the reason.

Step 3: Bulk-suppress the invalid addresses

Upload the invalid addresses to Klaviyo's suppression list as a CSV with a single "Email" column. Do not delete them.

Klaviyo's bulk suppression article describes the CSV route: keep only the Email column header, then go to Profiles, open the suppressed profiles view and import the file. They will appear with the reason "User suppressed".

Why not delete? Klaviyo says suppressed profiles stay in the account, cannot receive marketing email and do not count toward billing plan limits, while deleted profiles are "completely erased and no history is kept". A deleted dead address comes straight back the next time the same old CSV is imported. A suppressed one stays blocked.

Step 4: Sunset profiles that receive email and never engage

For deliverable addresses that have stopped engaging, send a short win-back series and suppress whoever does not respond. This is what Klaviyo calls a sunset flow, and it is the part verification cannot do, because these addresses are real.

Klaviyo's sunset flow guide defines the unengaged segment, which matches the prebuilt "Sunset (Email)" segment in its library:

• Created at least 180 days ago
• Received Email at least 5 times in the last 72 weeks
• Opened Email 0 times and Clicked Email 0 times over all time
• Active on Site, Viewed Product, Checkout Started and Placed Order all 0 times over all time

Someone who bought once and never opens is not in it. The flow sends one to three re-engagement emails, filters out anyone who opens or clicks, waits at least three days, then tags the rest "Unengaged = True" for bulk suppression.

Two cautions:

• Opens are noisy. Apple's Mail Privacy Protection downloads remote content when a message arrives, not when it is read, so opens get recorded for people who never looked. Klaviyo's bulk suppression article defines an active profile by a "human verified email click (non-bot) OR purchase within the last 6 months", a stronger signal.
• Read the modal. When you use Suppress current members on a group containing recently active profiles, Klaviyo offers to suppress only the inactive ones and lets you download a CSV of those it recommends keeping.

Our sunset policy guide covers choosing the window.

Step 5: Adjust your plan

Cleaning lowers your billable count, but Klaviyo will not lower your plan for you unless auto-downgrade is on. Klaviyo states that "deleting or suppressing profiles will not automatically change the Email subscription plan on your account", so downgrade manually if you have dropped a tier.

How to tell it worked

Watch the bounce and spam complaint rates on the next few campaigns in the Deliverability hub. It is under Analytics > Deliverability. Klaviyo's targets:

Metric	Healthy	Needs attention
Bounce rate	Under 1%	Over 2%
Spam complaint rate	Under 0.01%	Over 0.05%

If bounces stay above 1% on recently verified segments, the problem is upstream, in a signup source or integration. Other platforms' lines are in bounce rate limits by platform.

The takeaway

Klaviyo already suppresses bounces and complaints. Spend your effort on what it has not mailed lately: export, verify, and upload the invalid addresses as suppressions rather than deleting them. Sunset real addresses that have gone quiet, then downgrade the plan by hand.