Verify phone numbers Live

Check line type and carrier with Verify so your SMS goes to mobile numbers that can actually receive it.

Updated 2 min readMaintained by Landing Zone

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Verify classifies each phone number's line type — mobile, landline, VoIP, or unknown — along with its carrier. Verifying first means your texts go to numbers that can actually receive them, and your outreach spend goes to real, reachable contacts.

Before you start

  • Contacts with phone numbers in your workspace.
  • A sense of how line types differ — see Phone number types.

Steps

  1. Open Verify. Go to Intelligence → Verify in the Landing Zone app.
  2. Select the phone numbers to check. Choose the contacts or numbers you want verified.
  3. Run verification. Each number is classified as MOBILE, LANDLINE, VOIP, or UNKNOWN, with its carrier.
  4. Review the results. Prefer mobile numbers for SMS. Route landline contacts to calling instead — see Start an outbound call.
  5. Fix or set aside what didn't classify. For unknown results, check the number's formatting and verify again, or exclude the number from texting.
  6. Build your SMS audience from verified mobiles. Batch previews use line type for eligibility, so a verified audience gives you a cleaner preview and fewer surprises — see Create an SMS batch.

Why line type matters for SMS

Landline numbers generally cannot receive text messages, and messages to VoIP numbers are more likely to fail or be filtered. Texting them wastes sends and drags down your delivery outcomes.

That is why the SMS eligibility pipeline uses line type, and why a batch that contains unverified line types shows a "Send to unverified numbers?" confirmation — framed as a cost and delivery risk — before it sends. Your acceptance is timestamped.

Limitations

  • Results are cached for about 30 days — verifying a recently checked number returns the cached result.
  • A MOBILE classification is not a delivery guarantee. Delivery still depends on the carrier, the contact, and your messaging setup.
  • Verification checks the line, not permission. Batch and campaign SMS require VERIFIED consent — see SMS consent.

Frequently asked questions

How long do verification results stay current?

Results are cached for about 30 days. Re-verify older lists before a big send — numbers change over time.

Does a mobile result guarantee delivery?

No. Verification confirms the line type, but delivery still depends on factors like the carrier, the contact, and your messaging setup.

What happens if my batch includes unverified numbers?

Landing Zone shows a 'Send to unverified numbers?' dialog explaining the cost and delivery risk before the batch sends, and records your acceptance.