Shopify email verification
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Posted At: Mar 23, 2026 - 763 Views

Why You Should Clean Your Email List Before a Brevo or Klaviyo Campaign (and How to Do It)

You are preparing an email campaign in Brevo or Klaviyo. Your list has several hundred or several thousand contacts. But if you haven’t cleaned it recently, some of those contacts are probably useless — or even harmful to your deliverability.

Here is what Brevo and Klaviyo recommend, and how to put it into practice.

Why an uncleaned list hurts your campaigns

Brevo recommends cleaning your mailing list regularly to improve engagement rates, reduce the risk of emails landing in spam, and lower sending costs by targeting only active contacts.

The reverse is just as true: high hard bounce rates (above 2%), unsubscribe rates (above 1%) or complaint rates (above 0.2%) can lead to an account or campaign being suspended on Brevo.

Signs that your list needs cleaning

Brevo recommends monitoring your campaign reports to spot declining engagement, rising soft and hard bounces, and an increase in unsubscribes and spam complaints. These signals indicate that it is time to clean your list.

What Brevo recommends in practice

Brevo recommends cleaning your contact database regularly, identifying inactive or invalid contacts, and then adding them to the blocklist rather than deleting them — so they can’t be accidentally re-imported. Brevo also recommends double opt-in, sending emails only to contacts who have given their consent, and possibly sending a re-engagement campaign before blocklisting.

Brevo also lets you automate this cleanup with automation workflows: send a re-engagement email to unengaged contacts, then add them to the blocklist if they don’t respond.

What Klaviyo recommends in practice

Klaviyo recommends excluding unengaged contacts from most campaigns. It also advises excluding them from certain key flows, such as browse abandonment, while still allowing them into re-engagement or abandoned cart flows.

Klaviyo also recommends creating a Never engaged segment, then suppressing those profiles if they don’t respond to a final re-engagement attempt.

The problem neither Brevo nor Klaviyo solves for you

Brevo and Klaviyo mainly handle engagement, bounces and the exclusion or suppression of profiles after collection or after sending. They don’t replace a dedicated email verification tool for qualifying a database before import or segmentation.

That’s where upfront verification comes in:

  • If you run a Shopify store, GTMailHygiene scans your Shopify customers and subscribers, identifies invalid, disposable or risky addresses, and lets you segment them with tags and metafields before your next export to Brevo or Klaviyo.
  • If you have a PrestaShop store, MailHygiene PRO lets you verify and clean customer, order and newsletter emails directly in your PrestaShop back office, with scoring and export.
  • If you have a CSV file to clean before importing, GTMail-Verif checks every address online and returns a file with the status of each contact.

In short: the right order of operations

  1. Verify your addresses upfront with GTMailHygiene, MailHygiene PRO or GTMail-Verif
  2. Export a clean file to Brevo or Klaviyo
  3. Segment unengaged contacts in your sending platform
  4. Send a re-engagement campaign before blocklisting inactive contacts
  5. Monitor your metrics after every send: bounces, complaints, unsubscribes

Cleaning your list upfront prevents unpleasant surprises after sending — and protects your account on both platforms.

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