Verify an email address or an entire list
Connect a verification provider and use it before sending to uncertain addresses.
Supported verification services
- Kickbox, EmailOversight, NeverBounce, BulkEmailChecker, SendGrid, and Mailgun.
Verification workflow
- 1
Create an active verifier and enter its API credentials. EmailOversight also requires its list ID.
- 2
Use Verify Email for an individual address or Verify List for a saved list.
- 3
Select the verifier and review the available list verification options.
- 4
Already verified contacts can be skipped by the verifier workflow.
- 5
After completion, review statuses before scheduling a campaign.
Why list verification protects sender reputation
Sending to invalid, dormant, or role-based addresses drives up your bounce rate, and a high bounce rate is one of the fastest ways to damage a sending domain reputation with inbox providers. Verifying addresses before a first send, or after importing a list from an older source, catches these problems before they reach your sending server at all.
This matters even more for lists that have been sitting unused for months, since email addresses naturally decay over time as people change jobs or abandon inboxes. A verification pass before reactivating an older list is one of the simplest ways to avoid a sudden spike in bounces and spam complaints.
Building a verification routine
Verify new imports before their first campaign rather than after a bounce spike has already affected deliverability. Many teams also verify a segment before a high-value send, such as a product launch or renewal campaign, where deliverability matters more than usual.
Combine verification with list maintenance and suppression and blacklists so cleaned results are actually reflected across your contact base, not just in the verification report. Since already-verified contacts can be skipped, running verification regularly on active lists adds little overhead once the initial pass is complete.
Frequently asked questions
- Which verification services does K2Mailer support?
- Kickbox, EmailOversight, NeverBounce, BulkEmailChecker, SendGrid, and Mailgun are all supported as active verifiers.
- Do already-verified contacts get checked again?
- No, the verifier workflow can skip contacts that are already verified to save time and API usage.
- Should I verify before or after importing a list?
- Verifying immediately after import, before the first send, catches invalid addresses before they affect deliverability.
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