Every text you send to a dead number still costs you money. SMS providers typically bill per message sent, not per message delivered, so an invalid, disconnected, or non-SMS-capable number is pure waste. One bad number is rounding error. A list with 10% bad numbers, sent monthly, is a recurring bill for messages no human ever reads. Validating before you send is how you stop paying for that.
Where the money actually leaks
SMS marketing campaigns
Say you have a 100,000-number list and 15% of it is unreachable. That’s 15,000 messages you pay for and nobody receives, on every send. Validation cleans the list first by checking line type and deactivation status and confirming the number can take a text, so you only send to numbers that can receive it. Landlines are the biggest single bucket: across all our lookups about 32% of numbers are non-mobile, and only about 7% of landlines we check are SMS-capable (more on finding those).
Two-factor authentication
OTP codes sent to invalid numbers do double damage: you eat the send cost and the user gets locked out and files a ticket. Real-time validation confirms the number is active and text-enabled before the code goes out, which cuts failures and the support load behind them. Improving 2FA with phone validation goes deeper.
Sales and outreach
Cold calling and SMS prospecting burn rep time and budget on numbers that ring out or never existed. Validate first and your reps work a list of genuinely reachable people instead of a graveyard.
Real-time data beats area-code guesswork
Static databases and third-party lists fall apart the moment a number ports or a user relocates. CheckThatPhone runs a live carrier dip at lookup time for U.S. and Canadian numbers and returns:
- Line type (
dipCarrierType, plusnanpTypefrom numbering-plan data) - Recent carrier deactivations (
deactivationDate, within the last 45 days) - Carrier details and porting status (
dipCarrier,dipCarrierSubType,dipPorted) - An SMS recommendation (
action,deliverable,smsEligible) - GeoIP and timezone data
See the API documentation for the full set of fields returned with each request.
Gate every send on action
The simplest integration is one rule: call the API before a message goes out, and only send when action is "send". Anything else comes back as "unsubscribe", with reason saying why: a non-mobile or non-SMS-capable line, a carrier deactivation in the last 45 days, a blacklist hit, or, if you enable the add-on, a TCPA litigator match. Failed lookups don’t use credits.
What a first validation pass tends to surface
Beyond the dead numbers, a first pass over an existing list often shows patterns worth acting on:
- Lead sources that send a disproportionate share of VoIP or landline numbers
- Old numbers in your CRM that the carrier has since deactivated
- Area-code targeting that doesn’t match where your contacts actually are
Group the results by lead source and by when each number was collected before you decide what to fix. For a whole list, the bulk CSV uploader does this in one job, and the contact list hygiene use case walks through the workflow.
Running the numbers
Take 500,000 SMS a month at $0.0075 each (check your provider’s current rate) with a 12% undeliverable rate. That’s roughly $450 a month, about $5,400 a year, spent on messages that go nowhere. And that’s SMS alone, before you count failed voice attempts and verification retries.
Now the other side. If those 500,000 sends go to a 125,000-number list you message weekly, validating the list once costs about $125 on the 100K plan: $100 for the first 100,000 lookups and $0.001 each for the other 25,000 (pricing). Validation removes the $450 line item by catching the bad numbers before the send, not after the bill. The math is weaker for a list you message once, so validate the lists you send to repeatedly first.
Next step
The pitch here is simple: a fraction of a cent per validation against a steady drip of wasted sends. CheckThatPhone’s API validates U.S. and Canadian numbers in real time, flags line type, and surfaces the contact data you need to route smartly. Read the API documentation to wire validation into your messaging flow, or explore pricing plans and start trimming the waste.