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Phone validation

How to clean a phone list before an SMS campaign

PN
Written by
Priya Nair · RevOps & Phone Data Analyst
Jan 8, 2026 · 4 min read

SMS is expensive per message and unforgiving of bad data. Cleaning your phone list before a campaign means every text has a chance to land. Here's the checklist.

Validate format and status

Normalise numbers to E.164 international format and drop the ones that are malformed or disconnected. A wrongly formatted number simply fails to send.

Filter by line type

SMS only works on mobile numbers. Filter out landlines (which can't receive texts) and scrutinise VoIP numbers, which are more likely to be fake or throwaway.

Dedupe

Remove duplicate numbers so you don't text the same person twice — annoying for them and wasteful for you.

Do it in one pass

BounceBlock validates phone numbers, returns line type and carrier, and dedupes — alongside email and company checks — in a single upload, so your whole list is campaign-ready in minutes.

See how clean your list really isFree preview of your first 100 contacts — no credit card.
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